I have tried unsuccessfully many times to add Family Base to my plan. I have blocked numbers from calling/texting my son's phone, but it doesn't really help when he just calls them. I need to be able to block him from calling these people as well. He has a Motorola Droid 4 and I have a Samsung Galaxy S III Mini. I am told that the phones are compatible, but for some reason, I can't add this feature. I continue to get the same error message every time. What can I do?