Green Tree Servicing GT Servicing Rude, disrespectful rapid city, South Dakota

I was contacted by an account representative from GreenTree about a past due on one of my loans serviced by greenTree.  I have residential mortgage loans 3 are service by this company.
I have been sending in my payment to GreenTree and the previous servicer on about the 7th of each month and the "late date" is the 17th of each month.  I knew I had sent it...but maybe the post office lost the mail.

I check my bank account and the check had been cashed by GreenTree 4 daays earlier.
When I call back, the accopunt representative was having difficulty understanding so I asked for the manager.   Amber took the phone and quickly and rudely talked over me on several occasions stating that this account is past due and to "Stop talking over her" lol.

When she finally stopped talking, I asked her if she wanted to know what the issue was?  She stated that the issue is that the account is past due.
After finally getting her to calm down, I stated that I have several loans and make the loan payments with 1 check.  She stated that GreenTree would "NEVER" accept one check paying on several loans.  As I explained to "Manager AMBER", I have been paying with 1 check since 2006 and also for the past year with Greentree.

As it stands today, they took the payment stubs and check and applied it to only 1 loan.  Now i have 2 late fees  the "customer service people(lol)"  say the only way to get that reversed is to mail in a letter to."Customer service"  are you frigging kidding?

This is the worst loan servicing company I have EVER encountered in my 35 years and 33 mortgage paying.