Because they can!!! Hard to swallow but you will have to pay it.
We all had a shock going through completion. But once you get over all the problems you will love your new apartment! I am happy with everything now and it is a great location for investment. The only thing I am not happy about is my kitchen and that will soon be rectified.
Are you happy with your solicitor? If not I suggest you change- I woud definately reccomend ABC.