So i have removed the old gear cable on my Girlfriends mountain bike, The problem is the new cable that we have will not fit in the same hole the original went through. After trying for some time we tried to put the old cable in so it was still usable for the time being but that also failed, It goes so far in and then seems to get stuck on something inside the gear and nerve actually come out the other side.

Please help i can add pictures if that would make it easier.