Disappointed buy their service (Three Rivers)

I was at the three Rivers branch to buy an amplifier for a customer My customer stated that he suspected that his amplifier was blown so I went to cash crusaders to buy a new one

I then asked the cashier lady what the return policy was, she rep**** that I can return the Amplifier within 7 days and if it is faulty I can return it within the specified warranty time frame along with the install slip and the cash crusaders slip

Then I asked that if i did not use the product and it was still sealed if I can still return it as i was first going to test my clients amp and see if it could be repaired if not, I would use the one I bought and if it was repairable I would like to return it

I would have liked to buy it before hand as to not waste my clients time

Then suddenly she said no after saying that i can within 7 days

Seems to me that the staff there does not understand there own return policy or they are to lazy to do a credit note?