Iphone 14 tax free refund

Hi I bought the 2 iPhone 14 from yours Mapleview Centre on 2nd of Jully. i`m a tourist in Canada now and I`ll leave 6st of August so I want to make sure for this devices tax free refunds. I mentioned about that in store and they said i should go to duty free on airport and get a tax free form in there after that i will can take refund. But I concern is there a any different form or something which is I need? After all I have only receipt now is this enough for duty free ?

Thanky for help already. Have a nice day