Mortgage Company Didn't Use The Money I Sent Them The Way Their Customer Service Agent Said They Would, Do I Have Any Recourse?

My dad died a few weeks ago and I am in the process of trying to take over his mortgage as successor in interest per advice I previously received here. I contacted the company that currently owns the mortgage and they wouldn't give me any details about the mortgage at all, particularly when the last payment was made or when the next payment was due. I expressed concern about missing payments and the mortgage becoming delinquent while I was getting this whole thing sorted and the customer service agent offered a solution... She said I could just pay them money over the phone towards the loan and it would go into escrow and be applied to monthly balances as they became due. So I sent them two months worth of mortgage payments, thinking I'd be good at least until next month, if not the next two months depending on whether my dad made a payment yet this month before he passed (once again, no idea, and they won't tell me).

Fast forward to today, I called them to check on the status of things... To see if they got the stuff I faxed them like my dad's death certificate, the title transfer, a copy of my ID, etc.; stuff they told me they needed to proceed with the successor in interest process. During my conversation with this new customer service agent, she offhandedly mentioned that I should keep calling in to ask for updates because they only reach out via mail and it could take weeks for things to go back and forth if I only dealt with them via mail and risk missing a payment if I wait. I replied mentioning my previous conversation with their customer service, my payment, and the escrow thing and she said "oh... well I am not authorized to talk to you about this loan in particular, but in general, whenever someone makes a payment like that, the payment is applied to whatever balance is currently due and anything extra is just put directly towards the principal..." Seemingly telling me without telling me that is what happened with my dad's mortgage since, once again, they still can't give me any details about it.

So yeah, do I have any legal recourse here to get them to use the money I sent them the way they said they were going to use it? I specifically sent the money so the monthly payments would be covered at least until next month AT THEIR GUIDANCE. I get that they aren't stealing from me or anything, the money went towards the loan, and paying it off early is technically a good thing... But I am disabled from cancer and on SSDI, I can't afford to pay extra, I am just trying to make sure its paid on time... And now in a few weeks I am going to owe them a whole other monthly mortgage payment in addition to the two monthly payments worth of money I just sent them.

Thanks