Problems activating replacement SIM

I got a replacement SIM come through after losing my original.  I went onto the app where it prompted me to activate.

I pressed the activate button and it stayed on the ' it's activating' screen for about 5 mins without doing anything...I have restarted the phone lots of times and am unable to make/recieve calls, nor do I have internet access.

I am unable to activate the app no longer prompts me to....any advice please?