Incompetence upon Incompetence

I renewed my cell phone contract in Dec 2016 - and upgraded the handset. This is a 24 month contract, thus according to my calc, the last payment due end Dec 2018. However, I noticed on my bill for Jan 2019 I am still being charged for the handset. I called Vodacom, and the Call Centre agent counted the payments and agreed with me, 24 payments have been made. She logged a query, with ref # 1- ********** ********** . Next thing all I get is a notification that my query has been resolved, and closed. No phone call from Vodacom, no email, not a word. So I call again. I am told the contract was started in Jan 2017 - to which I requested the sign copy as my records says Dec 2016. After all, he who alleges, must prove. The agent says my query has been resolved and closed - at this point my patience are running thin so I ask for the Supervisor. Cindy comes on the line and I explain to her that not a single person has bothered to call me and tell me what the resolution on my query is. She logs another call and promises someone will call me back to explain the resolution . I am still waiting - no call to this day. The next thing, another sms that states my query has been resolved, and closed, Still, no phone call, this for query number 1- ********** ********** . Again, to day, no feedback. I am so sick and tired of Vodacom and every interaction having to be a battle.