Mackenzie Hall? Fakes?

I recently received a letter from mackenzie hall that we owe them over 2000 pounds. but i have no idea about this money. and the strange thing is they have used my maiden name on the letter. i received this letter on friday and they expect the money by tuesday. i recently read that the leader of mackenzie hall is also a leader of many companies but some where stricken from the register. and apparently a company they work with which i believe to have read is also one of the managers other companies j2 solutions. but the problem with j2 solutions is that apparently a lot of people have received letters, phone calls or people knocking at there door asking for neighbors information. is all this legal? are the companies even real? could this be a scam set up. i have checked on google maps and according to that mackenzie hall (which on there site says its set up in london and glasgow) but neither of these places are either verified by google or can be checked to see if this is the actual business place. all advice and information accepted please!!!!