Nespresso staff not helpful

I bought a new Vertuo Nespresso machine and after registering it, went to buy some capsules. The ones I wanted were not in stock, so the lady at the desk suggested I buy a "similar" one she recommended. I bought the "similar" ones, but only got to try them out about a week later as I first finished using the last few capsules on my old machine. The recommended coffee was absolutely awful, so I went back to exchange the other sleeves, and I was told "you're two days late we cannot change them". Eventually she said she could change them, but I would have to pay extra on the new ones as I bought the other 10 sleeves with a voucher and she wouldn't do a straight swop on the two sleeves of coffee even tho they were the same price. I felt that they hid behind the "system" that would not "allow" this swop and said they would not refer to the manager either. Really felt that they did not want to help.