Disconnected my Number

Cell c has disconnected my number and when i called their customer service they claim to have sent me a warning Sms saying i need to recharge to keep number active and i never received an Sms of that nature.so my concern is, if cant afford to buy airtime then it automatically means im going to be disconnected all the time? i mean really?Im sure on their systems they can trace and see the number is active and although i dont recharge i still receive calls.What ****es me off is that they say once a number is disconnected you cant get it back.This is a ridiculous and one of the worst networks ever!!