TFG Connect

I was offered a monthly airtime subscription with TFG through my American Swiss acc and took up the offer dating back 25 Aug 2021. I received R50 airtime per month at a discounted cash price. Nothing about my prepaid contract with MTN changed or was affected until the 25th May 2023. I bought my monthly data as I have been doing for years but I kept on getting a "no data balance" notification, however the actual GB is showing but I am unable to use it. Upon enquiring with MTN I was referred to TFG connect who informed me I have to buy airtime and convert it to data. This was insane news to me because I was nearing the end of my airtime subscription with TFG connect (ending 25 Aug 2023) and never experienced this before. After 21 months my contact was changed without my knowledge of any notification on their part, and I am unable to use my 4.49GB that I bought. This is money I dont have to waste and I am told the GB's cannot be converted back to airtime. Meaning it will just sit there and I am unable to utilize it until it expires. Can you please help me.