worcester combi boiler key doesn't fit into the holes of the loop?

The filling key that was provided with my worcester combi boiler doesn't appear to fit into the holes in the loop like the was it's supposed to, so I can't get it to lock into place and so if I turn the grey water ingress tap the water just comes out of the system instead of going in like the way it's ment to, so I would like to know if this is because I'm doing it incorrectly or if it's because there might be a manufacturing defect and if so what could be done to sort this problem out.