Gonna take a wild guess here. Find your activation key, wherever it may lie, and copypasta it back into Blockland after clicking the small "Key" button at the bottom of your Blockland window. If that doesn't work then the only other things I can think of are:
1. You're not connected to the Internet (or the Internet in your area is currently down)
2. Some security program is restricting Blockland's access to the Internet
OR
3. Badspot deactivated your key (unlikely), and the only way to check this is to enter the key you think he deactivated to see if it works.
Try that, if it doesn't work, post again.