Can't activate iMessage or FaceTime
Recently I switched carrier, from Mobistar to Mobile Vikings, but they told me there was something with the Apple-servers not being able to accept messages from that carrier so I couldnt activate iMessage. Before, when I was using Mobistar, I had no problem with iMessage. Today, like 8 hours ago, I switched back to Mobistar, but I still can't activate iMessage... I enable it and when I go to send and receive, there is a loading thingy in front of my phone number instead of a check sign.
I am using an iPhone 5c running iOS 9.3 (just updated)