Horrible experience.

Horrible experience.
After paying 700 for an Iphone 8 +, I bought 150 of accessories including 1 Samsung Fast Charge charger under the advice of the saleswoman, I go home and the charger does not work (it was supposed to charge in 20min at 100%!). I come back to the store to request a refund and they explain to me that in the store we do not refund! I explain that it is defective. They do not want to hear anything despite 15min of tests which prove it. And at that moment I was told that anyway this 80 charger is intended for SAMSUNG and will never do the fast charge in 20 minutes! Only solution offered by the "manager" - come back the next day to see with the saleswoman so that she confirms that I am telling the truth! Scandal. I call customer service who confirms over the phone that the salesperson should never have sold me this accessory with the iPhone 8 because it was not intended for. They
advise me to call "Frauds" at BT to file a complaint and get a refund.