MTN not assisting with query

I purchased the same deal through mtn on 4 sim cards. The advertised deal was that I would receive 30 GB day and 30 GB night plus a promotional 30 GB day and 30 GB night making it a total of 60GB Day and 60 GB night. I received the agreed-upon a deal for 4 months after which 2 of my numbers started receiving 30 GB day and 60 GB night. I have raised this with mtn customer support with the ticket being closed repeatedly with out them addressing the issue. I have been to the store as well as opened a ticket online. It has been over a month of constant back and forth and no one can rectify the error or tell me why the agreed upon deal is not being fulfilled on the part of MTN.