Bad service

I sent a faulty phone for repairs at Ackermans store in vanderbijlpark president hyper store last month around the 11 of March 2021 n received it back on the 20 of April they exchanged the phone for my Dad with the new phone only to find out that the phone was still faulty from the factory so on the 29 I went to 1 of Ackermans store in vanderbijlpark vaal gate was to told that I should send it to where I bought it they can't help me what makes me angry is that I was already in the store but they told me to go where the phone was exchanged I had to buy my Dad a new phone because he couldn't wait for me to go to another store why do we have proof of payment if you can't be assisted by any stores of Ackermans