Who I have the same questioned this topic

Because I was having reception issues, Verizon sent me a new SIM card for my Galaxy Nexus. When I put the card in my phone, it simply stopped getting a 4G signal (sometimes there is a very weak 3G signal - no bars), and when I attempt to make calls, I get asked if I want to call collect.

The directions that came with the new SIM card didn't mention anything about activating the card - it just said to put it in the phone. Do I still need to do something else in order to get the new SIM card to work with my existing phone/phone number/plan?