Mise de demeure from Urssaf for late payment

For years my bank account was deducted automatically when making my quarterly auto-entrepreneur declarations via the lautoentrepreneur.fr website.

However, unbeknownst to me, the “mandat de prelevement” was removed as a payment option, and I was not informed.
I suspect that perhaps it happened when I moved to another town with one digit difference in the post code, and thus being assigned a new SIRET number. Could that be possible?
So now half a year later I find out about this when I get a registered post from URSSAF that I have fines for being late in my payment.

I’m trying to figure out if I have any ground for appealing, being that I had not been informed and was thus unaware of the change.
My wife called URSSAF (who issued the letter) and they insist that there is no option to have an automatic deduction taken from my bank account and there never was. And that the only way to pay is online by VISA card (CB) or mail a check.

However, the only option I can find on the site is to re-enter my bank account info for a “mandat de prelevement” and hope for the best. No option for CB payment, no address to mail a check too. So I’m kinda stuck. Any advice?
Thanks.