Cell Phone being cut off every second week

On 24 November 2020 my husband's cell phone was cut due to payments which was behind as per MTN's records. On 24 November 2020 my husband spoke to Songeziwe Mbixane where after we sent all Proof of Payment through to them. The line was reconnected. On 2 December 2020 the same happened. We again sent through the proof of payments to ***. The line was reconnected. Today 14 December 2020 the line was cut again. Sending various communication again, struggling to get through to MTN as there system indicates that they are dealing with high call volumes. My husband's phone is still off and he needs same for his business. I would appreciate if MTN can resolve this for once and for all.