Depending on the rules of the network, if you can't get a response from an op in the channel, in order to try to get the problem resolved, you might try joining the network help channel (usually #help) and see if an op there is willing to assist with this.
Make sure you check any network rules and the MOTD to ensure that there isn't something along the lines of 'Network ops will not involve themselves in the process of banning or unbanning people from a particular channel"
Please note that the wording may be quite different from what I have put, but if the general meaning of the message is the same, and if no ops from that channel are willing to discuss the problem with you, then I'm afraid that you're out of luck.
