Number deleted from Vodacom Network

My line has been cancelled due to non payment, trying to make payment arrangements and was told that my account is with their collections and my number has been deleted. I was told by one consultant that even if I pay "I wont be able to get my number back". My contract ended May 2018, and I was three months behind. I was given a amount owing which has since increased not due to interest but due to the fact that June invoice was added to the amount. My question is how can you still carry on billing after the contract is done and is in arrears, but the bigger question is that the number has been deleted but they continue to invoice me . Speaking to people at the call centre does not help as they see the screen and answer accordingly, no escalation or feedback process in place.