Product: Mortgage

On XX/XX/XXXX one of 2 structures burned with 17K other buildings during the Camp Fire.

I had a reverse mortgage with Champion Mortgage ( CM ). After several months of attempting a short sale on the building that was left, " standing '', I changed my mind and decided to pay off the mortgage from Line A ( dwelling ) on my homeowners insurance policy. ( XXXX XXXX ). My insurance adjuster was told the payoff amount by the Loss Draft Dept at CM. She issued a check with both my name and CMs. I endorsed that check and sent it to CM to their loss draft dept in XXXX XXXX, NE. ( For exact address see attached mailer label. ) From the time the payoff check was written by my Insurance Co, signed by me and sent to the Loss Draft Dept, of CM, signed for by by a CM employee, 6 days had passed. The check arrived on XX/XX/XXXX. 
On XX/XX/XXXX I began calling to check on the status. XXXX, in the Loss Draft dept, phone number XXXX XXXX XXXX, ext. XXXX did not answer and I left her my information, asking for a return call. A second call was placed on XX/XX/XXXX with the same answering machine as the first call. 
I did not receive a call back from that " left message '' either. ( XXXX did tell me that she had called me twice and left messages. I never received either of those. ) On XX/XX/XXXX XXXX did answer. She was quite vague about the steps to " research '' my loan and said it appeared the " request to update had closed last night ''. I asked what would have to happen next and XXXX could not provide me with any answer as to how long this " Request to payoff '' would take to process. I pushed her for information and she finally passed me off to " XXXX '' in the Loss Draft dept. XXXX said it would take another 3-5 days to do the " pay off ''. " I first have to ask you if you want this check to be used to pay off this loan?, she asked me. " I'm sorry, but why else would my insurance company be sending you the amount you gave them as a " pay off '' amount ''. She replied, " Well it could be for repairs ''. 
Obviously XXXX was not seeing my hand written note, that came with the check, stating that I wanted to use the check to pay off the mortgage. And, ( and this is why I'm writing you ) she informed me that " gosh, interest has continued to accumulate on your balance so you will have to send another check for this extra amount before we can close the loan out ''. 
My question to you is this : At what point ; does CM stop adding interest? Seems to me that when they gave the final figure to my insurance company, that would have been the final amount. It feels like they are gouging or loan sharking. If they are allowed to do this, then when do they finally accept what is being sent to them. If I wire them the difference in what my insurance company ( as per CM ) calculations were, and their very slow time to process that check, then won't they want another check to " catch up '' from when they give me this amount they say is going to be owed. If they take another 10 days to process this " catch up '' check, am I going to be dogged forever, as time goes by between each check written and their bookkeeping dept at the Loss Draft section? 
Is this gouging, is this loan sharking, is this Senior abuse. Any one of these is quite sleazy. 
I would appreciate an interpretation from you. And, an action if this seems unethical, or illegal.