Why am I being denied a courtesy month, which is due to me according to my agreement?

I exceeded the data cap in Dec 2025, for the first time in over 12 months.  The Usage page message changed to "You have just used your courtesy month".  I was billed for the data overage in full in February, despite chatting with a customer service rep before the autopay was processed and being assured I would be credited.  After being charged the overage, I chatted with a second rep and was told it would be credited on my next bill.  My next bill is for the normal amount, with no credit.  Will my account be credited for this overcharge?