Phone really laggy but on contract?

Hey! I have a blackberry 9900 and, of course, as it is a blackberry, it is EXTREMELY laggy and freezes a lot... But the annoying thing is that it's a contract. It's a 24 month contract running from around October. The only way I COULD get out of it is to pay the termination fee but that's over £300 and I don't really want to save up and get the money and I really don't want to do that so any ideas? Anything would help! Thanks:)