MTN changes rules as they wish

I have had a contract with MTN for 20+ years. I have been using data share for my children for about 5 years now with no issues. I recently upgraded my handset and remained on MTN Business L package and I am suddenly not able to data share the promotional data. I was able to before the upgrade. According to the agent I spoke with this morning, MTN has removed the ability to do this. No communication was sent out regarding this and I am still paying for a contract that has the same data bundle set up that I was paying for prior to the upgrade. From what I am aware, businesses may not just take away an existing service? The data bundle is not unlimited so whether I use it or my children use it the data bundle is mine to use as I wish. The data bundle is capped so there cannot be abuse of this. I keep getting this stock standard (and ridiculous) response to my emails: "Kindly be advised that promo data cannot be shared but the inclusive bundles only, the change in data share is only on the number of users that you can share the data with. It used to be up to 20 users but now it's only up to 5 users. We unfortunately cannot do any changes on our side as this is an MTN" decision/rules and regulation.