[I stumbled upon this and am not currently using this method, just an observation.]

It appears that one of my credit cards did not process any auto-payment this period because they accepted statement credits as payment for the previous statement balance since the credits exceeded the previous month's balance. BTW, these credits were for purchases made in the current statement period, I could understand if these credits were from a few months ago, but they are for recent transactions so I'm shocked it would count as a payment.

So, would it be possible to avoid any payment for a few months by returning large amounts?

For example if my monthly average purchases is $1,000:

Month........Purchase amount...Return amount...Statement Balance
1..............$1,000.........................$0.. ................$1,000
2..............$2,000...................$1,000.... ..............$2,000
3..............$3,000...................$2,000.... ..............$3,000
4..............$4,000...................$3,000.... ..............$4,000