Hey
Was the sim activated by 48? Or was it a replacement sim?
Have you accidentally entered an erroneous sim pin and now the sim is blocked?
If so click on and follow the link below:
http://community.48months.ie/t5/Most-Popular-Questions/I-forgot-my-PIN/m-p/35067#M61If the issue has occurred due to erroneous sim pin input, it's best to change your sim pin to something more memorable.