Radis12 wrote:
My phone was tricked into logging into his icloud account and now I can't log it out, because I bought an old phone at a store that is not under apple's management, so I don't have enough records to tell them to remove that account from my phone, what should I do now?
You made a fatal mistake, and now the phone is lost to you.
Your phone wasn't tricked into logging into a scammer's Apple Account. YOU were tricked into logging your phone into a scammer's Apple Account. Then the criminal locked your phone remotely, and no doubt made some demand that you pay a ransom to release it.
Paying the ransom would be foolish, as there is no guarantee that the scammer would release your phone even if you paid. They might just keep extorting money from you over and over until they couldn't get any more money, then still leave you with a useless phone locked to their account. You would lose the phone and the money.
By your own admission, you do not have the proof of purchase documentation that Apple would require for them to consider removing Activation Lock under normal conditions. On top of that, the scammer will almost certainly have placed the phone into Lost Mode, and Apple will not remove Activation Lock from a phone that is in Lost Mode even if you have otherwise acceptable proof of purchase.
The phone is now fit only for recycling.
And for teaching this lesson: NEVER, EVER log into someone else's Apple Account with your next phone!