|Considering closing/settlement fees (including notary services) were already included in closing costs paid by borrower. Borrower has already paid.|
If your dispute is with a signing service, you can contact the title company involved to ask if and when they paid the SS for that file. You can even tell the TC that the SS hasn't paid you and maybe the TC will be nice enough to contact the SS and light a fire under the SS's bum. Your agreement is with the SS. Therefore, the TC is under no obligation to help you in any way.
IMO, the best things to do are to: 1) vet hiring party as thoroughly as possible upon acceptance; 2) get everything in writing; 3) do your job professionally and error-free; 4) follow hiring party's instructions regarding invoicing - if none, be sure to invoice them immediately upon completion of signing; 5) if payment is not received when expected, email hiring party by the 2nd day it's late and politely inquire (again, it's in writing). Any subsequent contact depends on their initial response. Again, everything in writing. In case you have to proceed to a collection letter or small claims court, then you have a paper trail showing there is an agreement and you followed procedure and attempted to collect on a debt.