How to unban from Fail2Ban[]
Easy:
iptables -D fail2ban-SSH -s XXX.XXX.XXX.XXX -j DROPssssssssssssssssss
Where SSH is the service that was banned (could be ASTERISK or any other)
And XXX.XXX.XXX.XXX is the IP address we need to unban
See How to unban from iptables