Answer:
working, do, recepit, exchange, refund
Explanation:
A:Can I help you?
B:Yes, please. I bought tuis mobile phone from you yesterday but it isn't working.
A:Oh, I do apologise. Have you got the receipt?
B:Yes, here it is.
A:Thank you. Would you like to exchange it?
B:No, thank you. I'd prefer a refund.
