MTN failing to provide good services

On 6 March 2020, I took a contrast for a Samsung galaxy A30 at MTN. They verbally explained their offers which were 20GB PM and 50 minutes everyday, they also offered insurance which I also had to pay monthly. The price that was agreed on was R379 including insurance. They told me that I won't pay for March because they said I took the phone on the 6th, which actually didn't make sense, they said I will start paying on the 31st of April. Then on the 18th of March 2020 I got a message saying "Dear Customer, Your query has been escalated" so I called the MTN head office and asked what was the problem, they twisted and denied everything that they offered to me, the data deal, the minutes and the price agreed on. Apparently price they mentioned when I called was R516 excluding insurance and the 20GB they offered was once-off and the 50 minutes were no longer offered everyday, they were offered every month. And when I called the assistant was rude to me. Now I really regret going for MTN and I want to warn everyone who is planning to go for MTN.