Stalling for time - no response

I bought a fridge from Dion Wired last week. I was told if not suitable I could return it within 7 days. I phoned them 3 days later as the fridge did not fit in the space provided. I have had to follow up every day and I get told (a) I must provide them with the invoice (which store doesn't keep a record?); then proof of banking details, then it has to be discussed with 3 different people, just stalling for time, then they will tell me my time is up. I was upset when I bought the fridge as I should have received a pensioners discount and also Massmart's policy is they will match a price if it is less at another store than what they are selling it for. Never happened, although I did enquire about it. Once again I am extremely disappointed in Massmart's service. Last time it was Game.