It's in the Direct Debit T&C's that a seasoncard where the direct debit has been cancelled is not eligible for renewal. Also the holder may lose all points accrued on that card. I very much doubt any refund will be offered, or is even possible to process, for a cancelled card. If a DD isn't paid, then it usually gets cancelled and has to be set up again from scratch.
The payment system and the SeatGeek ticketing system are competely separate entities, with a data feed between them so even if the club suspended the last DD, the ticketing system might automatically cancel the season cards, meaning it'd be a massive issue to get them up and running again for renewal and get new DD instructions.
So people may not like it and obviously it's no consolation if you've lost your job and are skint, but the club may have mde life a lot easier for people (and saved a lot of time and trouble for us and themselves) by taking the final DD. What isn't excusable, as I've said a few times, is their failure ot communicate this properly. They really do need to be more transparent.