No, you shouldn't have been more polite Chloe.
I think your mistake, if anything, was offering help a second time after he had said you were being rude.
I'd have shut the door in his face and immediately telephoned the company -perhaps I'm unnecessarioy suspicious, but my first thought would have been that he wasn't actually anything to do with them.
Hope you are ok. 
Are books a thing of the past ?
Change the name in a tv show /movie title to the above user username
How do you rebuild trust after it has been broken?
