I don't know why, but there are about 5 accounts that show up in suspended list, but they are really not suspended and the dns still points to my server, sites are live. I tried unsuspending. Nothing. I suspended, unsuspended, nothing. I forced a cpanel upgrade, nothing.
If the account has a bandwidth override, suspended it later, you could not unsuspend the account until you change the bandwidth override again.
Just increase the bandwidth and try to unsuspend the account.