MTN service suspended when payments was made

for the past 3 months I my service get suspended according to them for payments not made on my account N***. in the past I was notified that the payment has been received. i have NEVER missed a payment on this account. for the last 3 months i have to send proof of payment and after a few days my service was activated. my last payment for May 2020 was sent direct after payment was made. today the 17th of June 2020 I send for the third time this month proof of payment, My service is still not active and completely suspended. this contract is used for work purposes and have a huge affect for my work to be done. MTN service is pathetic, the customer are caused some much inconvenience due to their mistakes and clearly employees not doing their work