bad service with new sim card

I am driven to this by the fact that I have been sent from pillar to post, eventually given a new sim card, told store too busy for them to put it in, it would be no problem when i got home, only to find I had been given the wrong sim card, which now leaves me without service. at all. I have tried calling the store for 40 minutes now, no-one answers. I should have followed advice & used another operator.<br> No point anyone calling me on my cell now, as i had already rep**** 'yes' to the sim swop, so now my old sim not working either