Is this a complaint about another citizen or a complaint about a cop?
If a complaint about a cop, something smells fishy. There is no reason to "discuss." If he has any questions about your complaint, he can write them to you.
Otherwise, whoever makes the final decision about your complaint just needs to tell you the final decision and outcome, to the degree that he can without violating personnel privacy policies.
I personally would not "discuss" anything. This is not a negotiation. An event occurred, facts were presented, investigated, weighed, and decision made--hopefully.
We've read a few reports here where the supervisor just tried to "explain" why the cop did what he did and sweep it under the rug.