Data not working

I bought a 7 days data 2GB for day and 2GB for night on their App, for 3 days it was not properly working, I called their customer service and the agent reset it, it started working, then it started not working, i called again, to say this data is expiring without me using it, so what are they going to do, the agent told me to switch off for 5-15 minutes and call again if it's not working. It still wasnt working, i had to buy another data on my other MTN simcard and the data worked well. i emailed them to request a refund since it was their product that had an issue, not my phone and there is no response.