PEP - The most horrific service ever!

Yesterday after work, I went to Pepcell Jozini mall to purchase a C to C car cable charger and a type C/USB charger. I handed her the cable to cashier to pay. She then asked to see my phone which I found invasive. I asked her why and she said she needed to make sure that I have the right charger as the charger I handed her is very slow to charge androids. I reluctantly showed it to her though I felt insulted in my competence to know what I want and can afford. As loud as she was, she further left me in the counter, walked around it to the chargers' station and almost as if addressing the whole store, started showing me the cable charger that was ''best'' for me. She got a fast charger for both sets of cables.

I need to stress that this advice was neither requested nor warranted, not to mention embarrassing. She further shouted out the differences in prices, not mindful of the fact that I had already seen the prices for the charger I handed to her and the locked C to C cable I requested she unlocks from the rack. Feeling very belittled and embarrassed, I accepted all the charges which she didn't bother asking me if I was okay with or could afford it.

I bought the cables I was bullied into buying and left. Upon getting home, I realized that she had rung up a micro cable and not the C/USB as the one I had initially handed to her. I then called the store and luckily Phumzile answered. She insisted that she was trying to help me and offered no apology nor any form of remorse. The only thing she was sorry for was ''trying to help me!''

She then told me to return the item immediately to the store for an exchange as I still had the receipt. I related to her the distance between myself and the shop and the cost implications thrreof as a result of her incompetence. She reiterated that it wasn't her fault as she was trying to help. At that point I was emotional due to her ignorance, and also how she had bullied me in front of other customers in the store.

This morning I drove to the Pepcell store at the mall and Phumzile wasn't there. I was assisted by Qhamu, the store manager. I thought at the very least I would get the apology I didn't get given the level of inconvenience caused. She accused me of being overly emotional as I tried to relate to her what had happened. Yes, I was shaking and at the brink of tears, but I expected your employee in a management position to be sensitive to the fact that they serve different clients in the community who deals with things differently.
I then told her that I was registering a formal complaint with her as the store manager on how badly I've been treated. Her response was ''okay''. She did nothing to show that she was indeed registering the complaint. I then told her that I would be sending an email of complaint about this issue. Her response again was ''okay''. Based on that attitude I left the store very hurt and very belittled as a paying customer and a loyal clients for years! I felt I had suffered double jeopardy.
I need this matter mitigated tactically in a mutually respectful manner to avoid unnecessary havocs and fights. I couldn't use my phone as I couldn't charge it at hkme. I could not conduct business nor do my work as most of the files are on the phone. The employees at pepcell Jozini didn't seem interested in appreciating that fact both yesterday and today. I thank you in advance!