It would have been better if different addresses are used for each people. This can help us to know if the person paid or not.
It even makes keeping track for OP easier, if all addresses have a label, say "DoublerHunter's loan repayment". The moment a transaction appears, it's obvious what it's for.
What if it is altcoins? They always have just one address. I know they can have many addresses but the altcoins wallet developers makes it to be only one address. Are there USDT wallets that has many addresses?
Don't use shitcoin wallets that force address reuse.
And it sounds very much to me like an "exit scam" even though I didn't think that the word can be used in this context but it actually fits it.
I think the word I was looking for is "retirement plan".