Online check out not working

Same thing happened to me yesterday! In the end, I deleted my visa credit card numbers (cuz I used a few different visa cards), and ordered online by paying cash at the store. This afternoon, I went to a Walmart store but my order # said Walmart had received my payment, and there's no balance due! Called customer service and was told to get the store staff to call a multi-channel department #. The store staff called and that department was already closed at 1pm PDT! I called CS again, and the lady I spoke to was impatient. Anyway, I got home, checked my email and Walmart had sent me an email telling me they had received my payment which I never made. I was thinking of cancelling the order cuz it's really frustrating.