Service so **********_A|_Its crazy

on the 06/06/2013 I bought a blackberry handset at the Vodacom 4U store at westgate mall. I requested for insurance for the phone and signed the relevant insurance papers. A few months later I had a problem with my phone and when I took it in I was told that the insurance was not loaded. I produced all the relevant insurance paperwork for the insurance and the gentleman (Roelof Pieterse) that was supposed to have loaded it took responsibility for his mistake. His manager advised him to write me a letter on the company letterhead stating that for the next 12months he will take full responsibility to repair or replace my phone. This was on the 25.03.2014. On the 19 Jan 2015 I took my phone in as it would go off randomly and the speaker was problematic. I was told that I needed to pay R700 to get the phone fixed. I the produced the letter and I was send from pillar to post. Every time I call the staff have bad attitude, a manager is never available. I haven't had a phone in close to 3 months and they refused to give me a loan form. I am really at my wits end with this. Please assist