Harrassed after cancelling contract

We were due for upgrade so went to a Vodacom Store in Greenstone. Took 2 devices, a 5G and 1G. In the span of less than 1 week the data on the 5G was gone and exceeded the 5G to 7G! The 1G followed, all 1G and its equal night owl! Both devices having not in use most of the time. We returned to the store and the agent on duty was rude. Returned the following day with intent to cancel contracts but saw the agent (Bafana) that had done the upgrade so allowed him to try and sort it out. We gave it 3 days to receive an itemized billing, THAT NEVER CAME! We returned again and gave in the devices and cancelled the contract via Bafana. The manager wasn't in to sign off on the cancellation. We were told he'd do it the next day. My husband, the account holder spoke to the manager, telephonically, before leaving the store, on their line and told him he was done with vodacom since no one in store or in customer care, whom we had emailed about the problem, would lift a finger to sort it out. The manager tried to be difficult, telling him he'd pay more to get out of the contract. Well, we were within our rights having returned the devices within the 14 day period, which we later found out is actually 20 days according to the customer protection act. But Vodacom started debiting his account monthly until for separate reasons he had to change his account. Then when they didn't receive payment they started harrassing him telephonically, demanding payment. The agent, manager or both couldn't have cancelled the contract properly and our emails to customer care continued to be ignored when "escalated". When we went back for copies of the signed cancellation papers the manager had still not returned to work so we left it as it was costing us petrol driving the distance each time to get there and find out he wasn't in and the papers weren't ready. As mentioned, we have emailed Vodacom numerous times and twice we received notice that it had been 'escalated to back office' for resolution and we were supposed to get a response within days. WE NEVER GOT THOSE RESPONSES. Only telephonic harrassment. Then we received a letter in the mail demanding payment of the outstanding contract amount and the devices, which we DON'T EVEN have! We returned to the store again, finally meeting the manager, nearly a year later. He found documents and said he'd email them to the correct person and call my husband the next day. That was almost 3 weeks ago! NO CALL. Vodacom is all about the money, they do not care about their loyal customers. We were loyal for at least 10 years. With contract after contract and using prepaid vodacom sims for longer than that. Obviously we no longer use vodacoms services. We are out, R300 admin fee upon upgrage and R930,20 for the debit orders that they took despite the contract being cancelled. Now due to negligence on their part on so many levels we are threatened with legal action, excuse me!