MTN *****ed me into accepting an offer

I recently received a call from MTN offering to migrate my package. I agreed to the package I was being offered. which was 300 minutes and 5GIG. When they loaded my new package they only loaded 2.5GIG and they said that the other 2.5 was for night express. I told them to listen to the recording as it did not say anything about night express. I do not stay up late to use data. I want what I was offered.