MULFUNCTIONING NOKIA LUMIA 1020

in 2013 November i upgraded to Nokia 1020. within 6 months in June 2014 the phone freezed, couldnt charge or switch on. it was booked in pretoria van der walt. that time John advised me to take it to nokia hatfield if it start again. within a week of getting it back it freezed again and was booked at nokia hatfiled where they transfered it to head office as they said it has factory fault. the system was changed with new IME number, it freezed again and again and ended up having 3 IME numbers. all these times my information got lost. i communicated with repair at midrand i asked them to replace it with something of same value and they promised to investigate after i booked it in. i did but everytime they just brought the same back. i am now afraid of storing my mails and documents as it is useless but still paying close to R500 p/m. this phone is a disgrace to me as its appearance soesnt help me. i have proof of emails that i have been communicating with. now they contacted me saying i am due for upgrade and i am not even sure of proceeding with MTN as i received the bad servie of my life since i started with them. the promise they make they keep on changing when they have to do.