no service , invalid sim

I had a new sim card from my company but when I insert it to my iPhone 4 it shows no service. I tried to enable airplane mode for 30 seconds and when I disable it , it's now showing invalid sim, I tried to insert the sim to a different handset and it is perfectly working.The tricky part is, my old sim(currently inserted to my iPhone) and my new sim card has the same network provider, I don't know what to do I need to use this new sim card so bad , I'm just wondering if you could help me please I do really appreciate it Thanks 🙂