Nationstar Mortgage LLC Suspense Account, payments not applied properly Lewisville Texas

I have a mortgage that was sold to Nationstar Mortgage from Bank of America. 

I setup a bi-monthly payment to Nationstar in order to have save on interest over the life of the loan. Payments go through on the 1st-3rd of every month, and the 14th.

Nationstar has been holding my first payment, and not applying it to my monthly payment until they receive the 2nd half, which defeats the purpose of paying in this manner. They call this a "Suspense Account". This is where they hold your funds until all the funds are gathered.

In the same type of transaction, anything that is paid over the amount is put towards the same "Suspense Account". An example of this is when one of those payments went through on the 28th, instead of the 1st-3rd. They held that payment in the "Suspense Account" instead of applying it to the following month's payment, or towards the principal...they just hold it, and the interest accrues.

This is a very shady practice, and may be illegal? When you go to try to fix this, you must wait extrodinarily long wait times (read 15minutes+ for customer service, but you never start there, you start in collections due to "non payment" because your money is in a suspense account instead of being applied to your balance).

I hope to get this cleared up.