Not honouring warrenty

In Jan 2015, I experienced problems with my S4 handset which was running flat after 3-4 hrs and got very hot, I assumed it was the battery and replaced it, but the problem remained. I phoned the Samsung call centre, who directed me to USER Electronics in PTA. My phone was booked in for 1hr. and a reinstall of software was done, They said that the software was to be rolled back since software upgrades on the handsets sold by Vodacom tended to run the battery down. BUT the issue were not resolved and I returned it again. they then booked it in for a firmware upgrade, I collected it after a week BUT the PROBLEM was still there. I returned it a 3rd time BUT this time the service center said they would replace the mainboard. I fetched the handset after 2 weeks BUT still found the same issue. This time I asked for a written report on work done in order to take it up with SAMSUNG. They declined, saying it was logged on a mutual database and instead directed me to the Roodepoort service center. I booked it in but after 2 days was told to pay for repairs as the warranty was void due to generic parts and tampering on the phone....BUT SAMSUNG directed me to that repair center, WHAT A CON