Worst service for upgrade

On Saturday, I visited Vodacom4u in Sandton City and spent over an hour querying why, if I took out my contract in December 2015, I would continue to pay for my handset until March or April 2018. The first debate was when I had initially started paying for the handset. The system at the store cannot show details earlier than May 2016 this i requested the invoices from Dec 2015 to be emailed to me. 3 days later i was advised they were on the website (not emailed as requested). When i go to the website no such details are available.

I returned to the store today and again spoke to the store manager. I was told that the first payment was in Feb 2016 for Jan 2016 (no proof available though) but i would continue to pay until Match 2018 or April 2018. I have queried this but still no adequate answer.

I am simply trying to understand 1. When did I first start paying for my handset 2. When will my last payment be