Disappointed!!

I signed up for 120gb but I’ve been receiving 40gb throughout even when I check my balance after they loaded data it will only show 40gb instead of 120gb. What makes me even more angry is that I want to terminate my contract they are refusing to assist me. I called in April before the 26th they said I have to terminate it on the 26th. On the 26 Ty I went straight to MTN store at eastrand mall and they told me there is no need for serving a notice on the 26th of may the contract will be terminated. Yesterday I decided to call mtn and confirm the lady that I spoke with said she will schedule a please call me they will call me and they didn’t call me. Today I decided to call mtn and ask why didn’t they call me Keerat told me that their system is down it’s been two weeks now than why did they promise to call me knowing that their system is down. He is telling me that I have to serve a notice they can only terminate my contract in June and that he can’t assist me I have to call on the 26th. When answering the call they state that their calls are recorded but when I ask him to pull the recording he said he doesn’t have access and when I ask him to send an email to customer care department still he can’t. Wow I’m so disappointing with mtn mind you I’ve been using mtn for more than 15 years