I think this is some kind of a scam and can’t recommend to do it. You have to sign a contract, there is no escrow and in the app you are supposed to put in your private banking data. All details that can later be linked to your account here. And in the end there is not even a garantee that you will get payed for all of this since he won’t use an escrow.
I kinda feel the same way, user immediately said he would not escrow which should be a huge red flag along with an extended wait to be paid. Almost guaranteed this is a scam. Stay away folks.