On the 28^th of February, I won a game against shlevich by time out. On the 5^th of this month the game resumed play from the position it had ended on, the game was removed from my total game count and it no longer showed in my recent game history.

Look at my recent game history. The three most recent games were all lost by me, after the lost game on the 22^nd of February (against Scott-M) my rating was 1680 but after the very next game, also lost, my rating changed to 1712. According to my game history, I gained 32 points from a lost game. In between these two games is where the missing game goes, and with out it my rating makes no sense.

How did this happen, and how do I get the current game cancelled as it has already finished?

He is a premium member who is supposed to go on automatic vacation before time runs out. It probably glitched which allowed you to record the win. you should report that to the support staff to adjust your rating back to where it should be.

That is roughly what I was told when the staff got around to telling me that they had restored the game, they let me keep my rating tho :)

There was a server glitch on the 28th that, among many other things, caused a number of premium members to lose games that should have been set to vacation due to their timeout protection.

I'd venture a guess that the game was resumed deliberately by the staff out of fairness to the member who got a loss instead of a "paused" game.  Out of fairness to you, though, if this is what happened they probably should have given you a heads up.