Claiming cash orders not paid

In the same week, my sister and I both placed orders and paid for the order in cash in full, then when we go back on the app, it says our last order was not paid for and we're in arrears. These orders were delivered to our workplace so we have camera footage of the orders being paid for. Trying to get contact details from them are nearly impossible and they only have automated responses. Absolutely ridiculous, will never use again.