Airtime and data disappeared - not advised of transition from prepaid to contract

Hi. On the 22nd March 2023 I went to MTN Kolonnade for contract application which was successful. On Sunday the 25th I realised that I was not able to use my number for calls and called customer care. I was advised that there was a barring on my number - which I was not advised about. My data and airtime disappeared - I was never notified when my number will be transition from prepaid to contract. I meant my airtime and data back. This is *******