Handed over for no reason

I have been handed over to attorneys for breaking contract. I tried to upgrade in 10/2016 but after many attempts and no device eventually cancelled my contract on 01/03/2017. Received cancellation reference 1- ********** ********** . I then started getting smses from MBD Inc that i have been handed over for R2455.80 for so called 'breaking contract'. I never received any notification from Vodacom for breaking contract early, no statements reflecting outstanding balances. The hand over happened on 18 /08. Today i get a copy of my contract and according to Vodacom i upgraded on 06/10, but NEVER received the upgrade device. My ITC record has been marked as a bad payer! My account was in arrears but was settled in full on 08/09/2017. I need help. Vodacom is not helping me and Attorneys keep threatening me with smses to setup debit order for a contract i never had.