Should I exchange my blackberry for the second time?

I purchased a blackberry curve 8520 on contract from the Carphone warehouse about 3 weeks ago and I had to exchange the phone because the screen was faulty. I have now noticed that my new phone has three wobbly keys. I know that it is common for the whole keyboard to shift from side to side but these three keys are noticeably more wobbly than the others. It doesn't stop me from texting or anything but it is really bugging me. The trackpad is also wonky so it leans over to one side and it makes a weird noise if you slide it to the opposite side. Would you take this phone back and ask for another exchange? Or do you think they would not accept another exchange? I don't want to look really stupid going into the shop again if they're going to say it's nothing.