BB Curve :: It Won't Charge Properly

I've had my Blackberry Curve 9300 for about 7 months now & I've been experiencing this problem for the past 3 months. For some reason my Blackberry "chooses" the chargers that can charge it, i.e. If I use my wall charger, it randomly works, If I use my Boss' Car Charger, it works like any normal charger, I tried using my friend's wall charger, same problem as mine, then I tried another friend's Car Charger, this time it didn't work. I haven't installed any 3rd party apps apart from the usual package like facebook & bbm so I'm guessing the problem is elsewhere. The main problem is the "randomness" of my wall charger; sometimes it takes me a few minutes of pluging the charger to the usb port over & over again till the lightning sign shows that it's charging, but most of the time it takes me as much as 4hrs to get that sign to pop up, in which by that time my BB's already dead. The clock appearing at the time you plug the charger in has no effect as I press the return button every time after the clock appears, & the charging sign still isn't there. It's annoying because everytime the battery goes red are the time when I need it the most, like when I need to meet someone outside the office. I don't want to go through the inconvenience of purchasing a new phone of replacing this one as I have had lots of notes & messages that I want to keep but since there's a USB port problem, I can't even connect my BB to my laptop as it says it can't recognise the USB connection. I've tried with multiple cables as well & none can be recognised.