Pep Galleria cell phone

We purchased a cellphone for my old age mum on the 14th of December 2023 at the pep Galleria . Upon setting up the phone we found it extremely slow and apps on opening. We was notified in store that we have 7 days should we not happy with the phone . When I called the store the manager I assume an Indian lady was very rude and arrogant say we can't return I mentioned to her we will be taking another phone which will be more expensive but no is no. She said to me you should checked the speed when you took it . I have a 40mb fiber line and the phone is still bad. I am truly disappointed to the service I have received especially to some one who is elderly. Wake up Pep.