Sent xmr. Only partially paid? I searched and seen the same issue for Someone else in the past. It's less than 2$ (price keeps fluctuating though) and I already received a good deal and would feel like a dick if the vendor accepted it tonight. I have the funds especially to cover the cents it Was to start with.
Only my second time messing with Zion at all and I've noticed several flaws (possibly some fishy shit too) which concerns me for sure.
Did you ask Zion about it?