If the homeowner is making a partial payment, then the homeowner is not making the loan payment on time.  The contract, which is the note, outlines the term of repayment.  If you are having difficulty making payments, then the best thing to do is to contact the lender about alternative payment arrangements.  Some lenders may hold a partial payment in 'suspense' until the whole amount of the installment has been received.  Suspense in this case is not a term of mystery, but rather, that the partial payment is suspended while waiting for completion.

This really is not a situation where a consumer's rights are not being protected.  Communication with the lender at the outset of any anticipated financial problems is the best course of action.  Lenders above all do not want to own real estate. They are not very good at selling it and would prefer to avoid owning it.

The language on your contract or note dictates the terms in how you agree to repay your loan.  If the note states that the payment shall be considered paid only if it is the regular scheduled payment or the payment stated on your monthly mortgage statement.  This contract or note IS the law - you agreed to it and it is legal and binding.

It sounds like you are having difficulty in making your payment - make the right move by contacting your lender now and letting them know your exact situation or hardship.  Remember, lenders make money by keeping you in your home and lose money when they have to take it away.  You may be surprised by their willingness to work with you - but don't wait for them to call you - call them now.