not happy with service - a request to substantiate a claim of invalid bank proof of payment, ignored

I am not happy with the level of service from Vincent Gumpo - he has consistently and simply ignored my requests for him to either 1. provide me a confirmation that a bank transfer proof of payment that I have submitted | provided was indeed for the treatment received on 18 December 2023 2. Or, in the event that it wasn't, provide clarity on what the payment effected on 15 April 2024 was actually for then. Instead, I received a response that is worded with a threat of handing the account to attorneys - which smacks of bullying if the information requested to substantiate or to confirm what the payment made was actually for which treatment then. has not been provided