My payment not allocated to my account

I bought a device ADT for R3499 paid R1750 deposit to install then pay R875 for 2 months. Since 29.09.2023 l deposited R1750 they have failed to allocate payment despite sending them proof meanwhile they going to my account to withdraw it luckly there was insufficient funds. i have spoken to many agents who have been escalating the issue to accounts passed 2 weeks calling no solution promise to call no calls managers phones ever engaged my number very frustrated planning to cancel since no one cares.