Sadly that is not how things work.
We're not banning you because you might've scammed him or not. When selling accounts the original owner is always responsible for the accounts and is expected to be able to recover them whenever. Failure to do so results in a refund for the amount you sold the account for. That is a risk you take when you deal with account sales.
As for the ban, hopefully you can turn things around later on and cough 75m up from somewhere. Intil then, you'll remain banned.
Dispute closed.