Vehicle License Renewal through MTN Momo is frustrating

I paid a cash out from my Momo account to pay for vehicle license renewal. i was informed on Friday the 23rd Oct 2020 that I needed to upload my documents to *** with my vehicle registration number as a subject. I sent the documents on the 26th and also resent on the 27th and there was no acknowledgement of the emails I sent, I made queries to the customer center and was promised a call twice but no one has called thus far. i need an urgent refund to do my license renewal as I had just discovered that it had already expired. I'm very frustrated with their service