Killing Spree - Bug with scoring

deserteagle.50

Got tooled up and went in to Killing Spree, Level 11, first to get the 5 minute Achievement but just kept playing. My score ran in to the Billions, with x10 scoring, the Boss Helicopters would score 30Million+ and every baddie was Millions. I think my score got up to 12 Billion, BUT when I ended (played for about 15 minutes) the score showed up as NEGATIVE!!!! Then next day, my High Score was set to zero...AAAAGGGGHHHH!!!! Waste of time!

Is there a limit to the score you can get???? Or can this bug be fixed!