Putting

Need some help with putting, its never been my strong point, but i have had a good few rounds with no 3 putts. But now i have gone really bad again. We have really fast greens with lots of breaks now at crook. In my round last night i was getting really annoyed with it, my partner watched me put and said my putter head was not square at contact, i had the heal on the ground but the toe in the air. And to top it all off i have lost my distance control if i stroke it how i think it goes miles past so then if i try to do it softer it stops short. I cant belive the number of times i missed from with in 4 or so feet.
I have lost all confidence in it

HELP

Heel up or heel down doesn't really matter (watch the pro's they use all types), it's the plane of your swing that's important, although a heeldown style tends to lead to a pushed putt and lack of control of the weight.  It's easy enough to check and cure, simply lay two straight edges on the floor about the width of your putter and practice keeping the pane of the swing inside these - you'll probably find it feels like you have to swing out to in to acheive this.  Then make sure that you keep your eyes square over the head by gripping the shaft lower and lower until it feels like a comfortable stroke and the head will be square - guaranteed.  I've etched a couple of reference marks on my putter to achieve the same result.

Getting the weight and the break right is, unfortunately, a matter of practice....

Head down, lock the wrists, swing through from the shoulders, don't look up until your swing is complete.  Get one of the those indoor practice mats and get yourself consistent on that from the same distance every time (about 7 feet).  That means you have a point of reference as to whether you have to hit it harder or softer than your 'standard' putt.