Earring back wont come off...how to get it off?

I've had my cartilage periced when I was 14 so 9years ago last year my back fell out so I just put one of these clear plastic backs on and didn't pay it much.attention I recently went a got a new earing to put in it n i can't get the back off its no bugging I had my mom and my grandmother try couldn't get it and we tried twezers still no luck help me how can I get it out....sorry 4 bad spelling