Hi Aine,

Unfortunately, that's a well-known issue with those cards and you will need to replace the card itself (there are loads of relatively cheap options if you search online).

However, to keep you going until you get a new card, you can slide a butter knife into the slot next to the keycard in place and that usually allows you to start the engine. The knife can be taken out when the car is running and you will have to 'double press' the engine stop button to turn it off again, but it will at least allow you to drive the car until you get the keycard replaced.