My IGN has been changed by itself?!

I didn't play CF for 3 years ago , when I decided to return to the game I found that my IGN has been changed ! knowning that no body knows my password .

when I was playing the game I remember that I have purchased the item * Change In Game Name * and I've changed my name to : Ops.?

Now when I returned to the game after 3 years I found my name is : CTM_06592272 ??????????

Could any one tell me the reason ??