Product: Mortgage

I have had a Heloc from XXXX XXXX since XX/XX/XXXX that is serviced through Specialized Loan Servicing. I have been diligent in making online payments and even pay extra every month. On XX/XX/XXXX I requested a payment statement online which they will only send by mail ( they did tell me on a previous call that they would fax it to me in 2 hours but I never received a fax ). 
The day after I requested the payoff statement, I went online and made a payment for the full amount due on my statement which was {$2600.00} and I RECEIVED CONFIRMATION THE PAYMENT WAS RECEIVED, AND MY ACCOUNT WAS DEBITED. I then hit the request button for another payoff statement ( since the amount had changed ). When I received a payout statement on XX/XX/XXXX, I contacted SLS by phone to find out what the new balance was now since I had already made a payment. They advised me that my online payment of {$2600.00} made a week ago was in the process of being rejected ( the first I had heard they were rejecting my payment ) and they would send me a refund check in XX/XX/XXXX. They also advised me that if I wanted to pay off the loan, I would need to overnight them a certified cashiers ' check for another {$2800.00} ( the payout amount on the statement I received by mail ) before XX/XX/XXXX, thereby letting them hold over {$6000.00} when I only owe them half that amount. I asked to speak to a supervisor and XXXX pushed through a refund so that they will issue a check in the next few days and I should allow a few weeks for mail. XXXX said that once I get my refund check for the online payment, I could then send them a certified check or {$2800.00} before XX/XX/XXXX and pay off the loan. The other option is to wait until I have my funds back and make a new request for a payoff statement in XX/XX/XXXX. In the meantime, I should continue to make regular payments online so I don't incur late charges. Once all this is done, they will send me the overages ( which there will be ) in a check after 3 months. XXXX said the lesson I should take away from this if I ever do another loan is not to request a payout statement and then make an online payment. 
I think SLS has held my money unfairly. Once I made a request for the payoff statement, they should have either rejected my payment so that my account wouldn't be debited at all and they shouldn't be holding my money for months, At the very least, they should post a warning stating that any payments made after a payoff statement is requested will be rejected and returned by mail 2 months later. 
If I had paid the balance first and then requested a payoff statement after the payment posted, I would not be in this mess. I also think it is unfair for them to accept online payments from me but when I want to pay off the loan I have to take time off work to go to a bank, get a certified check and overnight it to them in order to close my account.The customer gets the raw end of this deal on all sides while they continue to incur interest and fees. It shouldn't be this difficult to PAY OFF A LOAN. 
I also want to mention that I made 3 calls today to SLS. The first 2 were not helpful ( one even suggested I could send up to {$11000.00} online even though I owe them a fourth of that ). They put me on hold when I asked for a supervisor and never returned ( I stayed on hold for nearly 30 minutes each time ). On the 3rd call XXXX was very patient and stayed with me until she transferred the call to her supervisor, XXXX who was patient and helpful as well. I don't fault the reps but I do fault the unreasonable policies and procedures.