Okay, odd situation here:

Last month's bill for me was, say, 2k dollars. I made a refundable UA purchase this month, got the full refund, now my "payment due" (to pay last month's balance) got lowered because it treated the refund as a payment towards my bill due and not as a refund. Is that how it's supposed to work? Wouldnt that mean that say, I dont have the funds pay the monthly balance at some point, I can just make a refundable purchase and cancel it to cover the "missing" amount and delay having to pay for it by a months, or theoretically for as long as I want to?