Passing the buck or bad workmanship?

I have been a Samsung supporter for the last 20 years of my life. Following the experience I have had with the S6, I will never use a Samsung phone again.

I convinced my Fiancé to take the S6, as the S5 was an amazing device. To my horror she did. She received it on contract from MTN. The first device had a bad pixel, which the company swapped for a new phone. The only thing we lost was all the cost for the data and time to set up the new device 1 week in.

She then had a problem with MTN and decided to buy her device with the Cell-C buy out option, which seemed like a good idea because of never receiving data from MTN after her upgrade, so we received a cheque with the buy out...nice.

The battery started lasting 4-5 hours at a time, then started to suddenly freeze and reboot. With her having a full time job and me being her only transport, we couldn't do anything about the faulty device for a month or two. It finally refused to charge. We took to the Samusing store in Eastgate to have it repaired under warranty. Here, I followed up repeatedly and finally had the phone back after almost 2 months only to be told it was fixed within 3 weeks. We were told that the motherboard was replaced. My question is still that if the motherboard gave a faulty charge to the battery, would this not damage the battery?

Following this ordeal. infelt so bad that I took her phone and gave her mine as she did not have any insurance from Cell-C, seeing that it is an MTN device. Now, with the cover of the phone never being taken off, a couple of months passed where all seemed well. After 3 months the battery started lasting 5-6 hours at a full charge, then it went down to 3. Eventually the cover started to come off of the phone, which was cry odd. I realized that the phone had bust at the seams because of, what I can only assume, is the battery expanding.

Samsung then said that the battery only carries a 1 year guarantee and that the phone was older than 1 year, so I will have to pay the full service fee to have it replaced...if other components are not damaged.

This all from a phone that is less than 2 years old. I logged this call with them and told them that the battery MUST have been changed when they replaced the motherboard because of the faulty charging but having spoken to a switchboard operator reading off a script. Nothing ever hit home.

This phone is now split apart and I will never, NEVER by a Samsung mobile device again. Either VERY poor workmanship or a total lack of accountability. I am extremely dissapointed in a brand I held in such high regard.