Heaven is right, this is pretty confusing. It sounds like you accepted a contract with a low hourly rate and the promise of a results-based commission. (I'm assuming the commission was to be paid as a bonus, since to be paid off the platform would violate UW's terms of service and get you permanently suspended.) It turns out you have no way of tracking when/how much commission is due, and the client is ghosting you.
Whatever amount of commission you were anticipating, you should now write off as tuition in the school of experience. Bonuses are imaginary until money actually changes hands, which doesn't seem likely at this point. (And if the commission was going to be paid off UW, the client knows full well you are in no position to squawk about getting stiffed.)
Don't close the contract, you'll wind up with no feedback which can be a drag on your JSS. If you choose to stop logging hours on it, the client may close it, in which case he'll be forced to leave feedback. Or he may just abandon it, which is fine. An idle contract that earned money won't hurt you.
I know diddly-squat about your business but the client is not legally obligated to pay you anything but the hourly rate you contracted. So if you mess with his campaign, you might stir up real and unnecessary trouble for yourself.
