The user has been banned so there is no way to repay the loan by the user. Please research before creating anypost like this:
'Banned' doesn't mean 'loan defaulter'. Since you haven't encountered such a problem before, we can't suspect a user based on this. Because the user is in contact with you and the timeframe hasn't expired yet. Though I am also not expecting to repay the loan. But if the user were honest, he would repay. So tagging a banned account for possible loan default doesn't make sense.
Probably the loan will turn into default but yet I do not think Op did the correct thing. Op could research and could post about the ban of the user.
In case that user becomes a loan defaulter, the lender should raise concern, though raising concern against the banned loan defaulter does not make sense. He could skip, simply since his account is gone forever; he would also be account farmers as well since he is banned for spamming. Who knows the reality? He might be honest as well; give the benefit of the doubt.