Credit still not allocated

Hi There A month later my query is still not resolved after I was told it will be sorted from April as it was late to allocate to March I am tired of having to permanently call the call center and keep explaining myself over and over again and be given reference numbers that their own colleagues can't read or pick up in the system I called MTN on Sunday the 23rd Apr and fair enough I was told to expect a call on Monday from the retentions department and I am still patiently waiting... Part of my wait included a visit to the bank for a debit reversal. I really need MTN not to look into this matter but to resolve it asap. I would really appreciate a tax invoice displaying the credit allocated from April till June, making it a total credit of 3months as promised Thank you