Claim declined unfairly

On the 30th of June 2016 I took out a phone on contract at the Mountain Mill MTN shop in Worcester (Western Cape). On the 14th of July 2016 I sent an email to Christina the lady who was helping me at the shop, asking her if I could insure my phone with MTN because my own insurance was charging me too much. She rep**** and said yes and she emailed me a form that I was supposed to fill in and send back to her. I filled in the form and sent it back to her. On the 30th of May 2017 I lost my phone. I blocked my phone & reported the incident to the police, I then went back to the shop to do an insurance claim for my phone. A lady by the name of Maccaila told me that she could not find any insurance details on the system. Luckily I still had all my email correspondence with Christina. I then showed and forwarded all the emails to Maccaila. She informed that MTN had recently changed insurance companies and it looks like the old company did not load my insurance. She told me she would sort it out with their new company and have the insurance loaded so they could process the claim. Today they are singing a different tune. I am told that they will not be able to assist with my claim. They say I had a year to check if I had insurance. As far as I know I had insurance because I completed the forms that were sent to me by MTN and sent back the documents for processing. It is not my fault that MTN’s insurance companies did not do what they were supposed to do in this regard. It is now more than 2 months than sitting without a phone. MTN and their insurance administrators have been giving me a run-around. Today I am told that my claim is declined! I received an email saying "We tried calling you several times and to advise that claim remain decline due to no cover , your insurance was app**** in July yet you are claiming for May. You can call : ********** 084 for further explanation as we we trying to call you several times to notify you". After I have sent them all the proof with regard to my application for insurance. I am really not happy with this. This is just not acceptable.