ok, had a look at aheadphone jack here and I think I know what you mean. the flex you have bought is not attached to the metal part that screws on to the rearcase/frame. if you place the flex with the "mushrooms" facing up and the flex coming from switch is furthest away from you... you can use a fingernail to gently lever the plastic mushroom away from metal fixing while holding on to metal fixing with other hand. if you try to lever the flex end I think you will end up damaging the gold filaments.. It is then simple to replace the new flex in to the metal fixing. the mushrooms didn't break/snap etc but just take it easy.