MTN *****s indirectly through unjust data regulations pertaining to promotional data in contracts

I have honestly revel ed pathetic service at best from MTN so, I renewed my contract and now promotional data as part of my upgraded contract, however I purchased data when my data from my contract benefits was depleted and soon as my contract benefits came through 2 days later my data which I purchased that's part of the weekly bundle plans hasn't been used and it expired without me using 982Mb and they charged me R70 for this and their excuse is that in terms of tgere regulations promotional data gets used first before any other expiry data I think that's really unfair and in itself it's thievery to charge someone for something and then rob them by not using the data that expires first instead of promotional data. Further more do not offer services to contract customers with the intentions of not delivering as intending, we work hard for our money and it shouldn't be ****** from us through unjust regulations if someone pays for something just give it to them be fair that's how business works ethics is important to adhere to I do not intend on renewing any contracts with this network once the current contract expires after this experience