I don't have any buy from the user "ScotsRon", maybe did you buy it not being logged? You should have received an email from my donensbourgh email account. Write me back with the same email you bought the game, just to confirm it, otherwise I'm afraid I didn't receive any money from you.
About Matilda, just ask her about fishing and the door will be automatically open, just go to the manor area and the door should be open (if it's morning). In case it's not happening, just restart the game, maybe something is not working as expected....