Untrusted Bank

I'm very Disappointed by Capitec Bank. I've made payment with my app then the 3rd party said they haven't receive funds. I've been going to the branch requesting for proof Payment but unfortunately they are unable to assist. consultant together with the Branch manager made numerous calls without success now am wondering how in this world whereby people that I trust with my Money cant help. it was like am requesting the impossible. can somebody tell me what to do. Thanks