the cs-account is not resticted to the internet account/ip you used for signup (most ISPs uses dynamic IPs, so not even possible to stick a cs-account to a IP-address)
if the box + cs-account works on another internet connection it seems Mgcamd is configured correct (and your cs-account is also not locked by the server)
if its not relaed to a reception-problem of Astra2/28E I think the network connection is not working at your home (wrong network configuration, damaged cables)