Hi,
i have got the same problem with my sim card.What i have done is to put a small piece of plastic tube on the end of the sim card, so when it goes off stating no sim card or poorly inserted, i just pull it out slightly and then back into position.This is alot easier than getting a needle or similar object to enable the removale of the sim holder.I did try a new sim holder but that did not work any better.
Also put a little bit of glue on the two edges so that it does not allow the sim card to go right the way in, otherwise you will still have trouble in getting it back out without the aid of a needle.Even if it does not lock right into place, it will still register.
Thats about all i can say on the subject, as the dealer said that it is not under guarantee.
You will find it loads better doing it the same way as myself i promise.
Best regards,
Steve.