Missing Data

I signed up for my month to month data Contract with MTN and I was told I have to make payment from the 25th and before the 1srt of each and every month. On the 29th I want to pay for my data which was before the 1st the following month. On the 1st I didn't received my data I waited till the next day because I data that was left on the previous month. After few days of not receiving data I didn't contact with MTN they look the ticket and they said to they will manually load my data within the next 72 hours. I made a follow-up call after 72 hours I still haven't received my data I called you the call centre to give me a refund I was told that I'm not gonna get the refund cuz all I need was my data all my refund because I haven't received the services I purchased