MTN no longer offers my data package and in-turn *****s my accrued data

I've been a loyal MTN customer for 22 years not and have been a contract subscriber for 13 years now. I have multiple packages with them and one of my packages is a 400gig LTE for home package.

A few months ago, I received an SMS that my subscription fee will be almost doubled if I don't upgrade or sign-up to a new contract. My intention was to renew my current package as it serves me and my family well. Unfortunately, MTN no longer offers that package. The offer 5G LTE (unfortunately, my area is outside of the coverage) and the "normal" LTE is a maximum of 200gigs. I was left with no other option but to cancel my package upon expiration of the contract. During my call with MTN's agent I was informed that all my accrued data will be taken away once the contract is cancelled.

How is that fair when I was diligently paying for that data. I did not get it for free. I paid my hard-earned money for that data and simply taking it away because you are no longer in a position to provide me with the package that I desire is downright ********.

If you want "your" data then pay me back the estimated monetary value of that data. You absolutely cannot have your cate and eat it.