Group Emails

I just started as an admin for a group and had sent out two emails to let the group know about the change and some admin work we as a group have to do. I sent them once and found out from a couple of cranky members that they had received duplicates of the two emails and would I stop emailing so much. Needless to say I couldn't reply to them (another email) but I checked my sent email and it shows one send for each. Was that just a glitch or did I do something wrong. With one of them the system came back and said I couldn't send spam?