Rotten service from MTN - They definitely don't brighten my day

I upgraded a contract at MTN College Square Bloemfontein. Took a Samsung S22 Service was good and they were very eager to sell the upgrade. The new phones battery ran down completely in 6 hours. I took it back. The assistant then called her manager, a Liesel, to speak to me. She then told me that the phone might not be faulty but my expectation might be too high. Expecting a phone battery with normal use to last a day is a high expectation? She told me that she carries a power bank with her. She also basically said that it's better toupgrade online and not at the branch. I then handed the phone in for them to send away for testing. It is 3 weeks now. I have called about 40 times and the call was answered twice. First time they said the phones not back yet. Second time, same story so I had to tell them to follow up. Marissa then said she'd call me back. It's a day later and still no response. They do not answer the phone - ***. I called 083135. They are also no help. Keep telling me to go back to the branch. The fact that I'm out of town doesn't matter to them. They can't be of any assistance. How do I find out where my phone is if I can't get assistance from MTN?