As I know, Amazon will identify false reviews in two ways:
1.Review frequency: If the frequency of the review is too high, it will be regarded as the seller control review quality. Which will trigger the Amazon warning system. After that, all the reviews will be deleted.
2.IP repeatability is too high: Amazon may delete it directly if it scans the same IP address with too many comments on different accounts.
For different products? What I tend to do is to periodically go thought the products (all sorts not tech only) and review them in batch. Is Amazon expecting each review to happen individually at different times?
Hey man, Sorry to hear about that. I’m from the US so I don’t know if they specifically changed the rules for outside the US, but the same thing happened to me. I still have no idea why but one day all my reviews were gone and I couldn’t post new ones on products I had just purchased. I contacted customer support, It took about a week, but they got it all back for me and I am allowed to post reviews again, I suggest calling their customer support and, if you really want to be able to review again, don’t stop talking until they agree to fix the problem. If you are a Prime member they will do bascically anything to keep you happy!
it;s the same for me on iphone 8, its their stupid new UI for mobile, one photo, really, that’s all Amazon? goofballs
Like I said to the other guy who had the same problem Because it happened to me as well One day all of my reviews were gone and that was no longer allowed to put new ones. I contacted their customer support VIA PHONE, CALL it’s the onlt way to get it done. After a week, they were back and I can review again
Call customer support tell them what’s going on, I had the same problem and they fixed it within a week. If you are a Prime member they do anything to keep you happy, but you MUST CALL NOT CHAT OR EMAIL Good Luck
LIke @Chris_Renshaw said, maybe the best way to know their review rules is to contact their customer support.
Prime member? They WILL fix it!
This was exactly what I did.
No chat, no email.
Just a call.
Thank you for the hint!
As I am only a very polite,
friendly and eloquent old gentleman (not a prime member) 
I could convince the young lady forwarding my issue to the authority responsible.
And Voila: All restored. 
Really?! Yo that’s awesome! Congrats man, I’m glad I could help! I hope the word spreads and more people are able to right wrongs done to them!
There is always a human being you talk to.
And talking is much more individual than an email.
And he/she is only doing what he/she is able to do.
And you must know that this what happened is not his/her fault.
So talk quiet and friendly.
A rule for live:
“Friendliness and kindness cost nothing,
it’s free and helps a lot”
Yeah I just posted something like that on my thread about how when you call up you must understand that these people are getting paid basically nothing to do this job which is ridiculous. So the last thing you want to do is take out your anger on these people because they will not be willing to help you. Instead do what you suggested and what I suggested is just be nice be polite and understanding even though you may be in a bad mood because you stuff got deleted, if you’re just nice to the person they have no problem Reinstating your reviews and most likely account to it for some reason that was deleted other than a major violation of their terms of service.
Exactly!
I have a conflict when I call up helplines/customer services…
I worked in a call center for 8 years, it was hellish n brutal, and damned good fun! It all depends on which company I was representing. The call center was an OUTSOURCE company, we represented several BIG companies, including government helplines (swine flu, test calls to British Embassies (make sure emergency procedures were solid), UK passport office).
Back to calling up myself! Due to having done the above, I know how I EXOECT to be dealt with, as it’s the way I dealt with customers/clients etc. So my expectations are extremely high, but rarely do i get that from STANDARD operators. Now add to that terrible disappointment with my mental health, and my calls can get quite interesting!
So I usually go to ceoemails.com and search for the CEO/director of a company, and calmly (sometimes (quite often) use sarcasm, and use their own mottos/taglines against them) write a strongly worded email. I try not to call up, if I can help it. lol
Meh. I mean if YOU have to go that route I guess whatever works. But calling them and talking calmly, being nice, usually works.
Speak of the devil
Good news!
You set a good example for other people!
I wrote them over the span of 4 months. After the 5th contact, I emailed them. I just checked today. My ability to leave reviews has been restored. To add, I did tell them that I was a prime member and I was very unhappy that this had happened.
They never replied once I said I was a prime member, they just restored and no notice was given.
They seem to care less and less about Prime Membership, the owner of Amazon is making over 1mil a day so… but thankfully they resorted it. I can not say this enough, if some one else has this problem, CALL them, ask to speak to a manager, then state our case. As long as you didn’t purposely violate their TOS, you should get it back. Following my advice at least 5-6 members of this community had the same problem fixed.
I have to ask, did you get the 1mil a day from watching Reckful on Twitch? Just wondering how small the world is. I was just watching him talk about Jeff Bezos.