Airtime and minutes lost due to suspended account.

Due to Covid-19 I was unfortunately without a job due to the fact that I am a hairstylist. I have settled my account in full as I am working again. I requested if my airtime that was locked be reinstated but to my disappointment I was told I forfeit the minutes and airtime for the 3 months the account was suspended. To my knowledge I know that I was in arrears not to my doing but due to a pandemic worldwide. My question is why? I paid in full and expect what I paid for to be rewarded what's due to what my contract state I should get monthly. This has never happened before if my account was paid late and suspended before.