Mtn not staying true to their contract.....

I took out a data contract at Mtn on August 2019,40 gig day data and 40 gig night data,everything went well up to 12 March 2020 when i received 20 gig day 20 gig night,i phoned several times 135 to resolve the issue yet i had to go to Mtn Store Springs where Thabo assisted me to log the querry.Yesterday i phoned 135 again to hear whats going on,so then i was told i was logged to the wrong department so it was resend,my problem is i am almost out on data now and would have not been in this situation if Mtn stayed true to their contract agreement,me as a long standing customer get treated this way of waiting and still waiting for data that is owed to me,if i dont pay my contract then they will certainly cut the line,i really dont feel well about this,at the end of the day i must go buy data and load,while Mtn owes me 20 gig day 20 gig night.