Monthly Agreed upon payments allocated elsewhere

At the beginning of last year I had an agreement with PathCare accounts that I would pay R500 monthly in order to pay off accounts pending from 2017 for my deceased mother and my dad. R250 is meant to be allocated to each monthly, however when I requested the balance of the account it was not sent. Instead I was told today that my last payment was allocated to a new account for October 2018. This was not my agreement with PathCare and I have no intention of paying other accounts when the agreement was based upon accounts pertaining to 2017. I am paying these outstanding accounts monthly purely out of good faith as my mom is deceased and my dad is a pensioner. Yet my payments are being allocated elsewhere without my permission.