Going to collections hurts initially but will never hurt the account again. If you can afford to pay it off, do so, if not first dispute it (even if it's legit, if they don't acknowledge the dispute it comes off your report) then forget it, don't answer their calls ignore them. It will go away in 2 years.
Pay your credit cards off then spend 30% of your limit and pay it off every month. With Time you'll recover.