Bad Service and poor quality device

In Aug 2015 I got an S6 Edge Red. From inception I experienced bad network coverage.Initially I thought it was normal poor network coverage until I monitored and check coverage of people I am with who are on same network. I would go to a different city and still experience the problem.Nov 2015 I went to Vodaworld in Midrand, the first time I left without being helped due to the long waiting period of close to 2 hours. I made time to go again on a Saturday in November where I was there for close to 2 hours. The consultant performed a software update. To my disappointment I still experienced the poor network. Mid December I went back to Vodaworld,waiting period still terrible.I was prioritized as a Red Advantage client but spent a lengthy period with the consultant preparing my phone for repairs. The phone was at repairs for over 7 days. On the 23rd of December 2015, I collected my phone. On the 9th January I was BACK at Vodaworld and I met with the second in charge, he changed something remotely and said this is would help with network problems. In 2016 I am still stuck with a phone that is not working properly meanwhile every month without doubt I part with about R1500.