Mtn data contract (service provider breech of contract)

In 2019 I took out a contract for a router and 40 gig day and 40 gig night data. I was being provisioned correctly until I realized that my data was getting deleted very quickly. In October 2020 I checked the balance on my router 2 days after it was loaded and I realized that I only had 10 gig data. I called mtn and they confirmed that they were shortchanging my data since February 2020 due to a system migration. They proceeded to restore my data for October 2020.i asked about the data lost from February to October and that's when the problems started. It's over a month now I've been calling, making countless follow up and not getting any joy out of them. I then contacted icasa who stepped in. The problem is that the missing Dara has been restored but they are only giving me 1 month before it expires. I paid for this data that they shortchanged me for a period of 6 months but they expect me to use it in 1 month. This is very unfair and I believe that I have the right to get my money back since they are nilot upholding their part of our contract. It's been a month of back and forth with mtn and I'm very unhappy.