Don’t! … Send all issues and problems detailed and with pictures to support@eufylife.com and if they are malfunction, failing or useless, you will get replacement cams for them!
Sending all back to amazon to get refund and then buy them again (for the much higher non discounted price) would be stupid.
I alread had several cams failing and falling out in the past 8 months, and all got replaced by eufy support, which done a great job regarding this!
And last but not least:
Don’t forget that you have WARRANTY! … So they “have to” repair or replace it.