refusal to replace handset

I have been a client of 24hour mobility for nearly 3 years, I I have never skipped payments to them , however my employer gave me a new cell phone in November 2014 with a new line , I then proceeded to use my insured line with 24hour mobility as personal phone and line ,I went to Zimbabwe in December and only came back on the 15 of January , during that time my handset with the insured sim card were left at my house as I had no need for them , i then used the insured handset with the insured sim card for torch purposes to shine light at night as i was changing tyres, the handset got lost in the process as i must have left it there. Upon realising this i made a clam to 24hour mobility who rejected because ,according to the extremely rude call centre agent , i had not used the phone for a while, alas i had been paying insurance for this phone even though i was not frequently using it.the call centre agent was extremely rude even though i tried to explain to her the details of loss, to which she said i can cancel my insurance