WeFix unreasonable, petty, and dishonourable

My iPhone XS was working perfectly, but required a new battery. WeFix Woodmead replaced the battery in Dec 2021. I then immediately noticed that when the phone battery would decrease (with normal use) to approximately 20-30%, then when I took a photo the phone would instantly die/switch off. The problem was inconsistent, but frequent. To switch the phone on at that point would require connecting to a power source. The phone is effectively unfunctional, and I would have to carry around a power-bank to switch it on again. When I got a Satisfaction Enquiry (Ref WMPH326949) email from WeFix shortly after the battery replacement (remember you can’t phone them), I rep**** with the problem. Tobogo, the store manager said I would have to bring in the phone, but that he would need to keep it for at least 24hrs. My profession (a doctor on call) would not allow me to be without my phone for that period of time – as I explained to Tobogo. I now have another phone, so I took the phone back to WeFix Cresta (a 30 minute drive now, as Woodmead has closed). After only 24 hrs, the technician phoned to tell me he’s tested the phone and there’s nothing wrong. It’s inconsistent, but frequent! 24 hrs is not long enough. I insisted on speaking to the manager. Kelebogile phoned me back. She says since the battery is out of warranty, I must pay for a new one. I explained that the problem began immediately they replaced the battery, therefore the warranty period is irrelevant. They caused the problem, most likely with a sub-standard battery, they must make it right. After stubbornly refusing to hear my point, out of desperation to getting my phone functional, I suggested to Kelebogile that I was prepared to split the cost difference. A new battery with labour is around R699. Cost price for the battery is probably R300. I suggested I’ll pay R150, and they must deliver the phone. It’s not about the money, it’s about the principle. Kelebogile foolishly refused, insisting I pay for a new battery, despite the problem beginning immediately. A few hours later I received an SMS to say I must come collect my phone. Come on WeFix, what bad publicity, for a R150 cost to you! I have not collected my phone yet, and will not until this damage is resolved. I have found WeFix to be dishonorable, and certainly not interested in making good on my months of frustration. The customer certainly doesn’t come first with WeFix. How about a name change? WeDon’tFix or WeDon’tCare or WeAreUnreasonable.