What should I do to fix this problem with joining Minecraft Servers?

My friend made a Hamachi server. I joined it, but when I join whenever I dug a block it would reappear and not give me the block. It wasn't near the spawn so that wasn't the problem. Also, whenever I would say something it wouldn't show up on the chat thing for like 5 minutes. The game didn't lag at all so it's not that. 5 other people join the server and play fine. Does anyone have an idea of what I can do to fix this?