Hello I am a lawyer with over 15 years experience. I will try to help you with this.
Can yo tell me when did the rep come round, when was the order made and do you remember what the rep said? When did you write to the company. Also did you sign anything and if so what does that say about cancellation rights? If you give me this information I should be able to give you a useful answer.
Was there a contract you signed that had cancellation clauses?
Good. That sounds like things will resolve themselves. I would suggest that you make a note of that phone call. Note the date and time that he called, the number he called from and what he said. If you have itemised bills you will have proof of him calling you. It is best to do this juts in case he goes back on his word. Without a specific cancellation clause then you would have 7 days to call it off under the doorstep sales regulations. 28 days is the standard time for cancelling credit agreements. Here you were entitled to rely on the representations of the sales rep and fortunately it looks like he wants to do the decent thing.
I hope this was a helpful answer but please ask further questions if you have any.