Disapearing gun?

Hey guys, A while ago I bought ZP black market crates and won an M4A1-E. about a month after that I went off to work. and when I had gotten back 2 days ago it had disappeared.....and last night a message came up telling me that I was already logged on. then after that another popup came up telling me that a hack tool was detected. after that I couldn't log in for about 10 minutes....and it kept telling me that I was blocked from the server for 0 hours and 0 days??????