There's a fair bit of enthusiasm for ticketing systems in the sysadmin world, and it's not hard to see why. But I'm going to be a contrarian here: while ticketing systems are all well and good, you should absolutely not require users to use them in order to interact with you.

The problem with ticketing systems is that they're like bug trackers; they're internal systems that are almost always filled with fields and procedures that exist for your needs. Your users should not have to fill in these fields and jump through those procedural hoops, because they don't give your users any benefit; they just help you.

This doesn't mean that you shouldn't have a ticketing system; it just means that you should take freeform problem reports by email or whatever, and put them in the ticketing system yourself. And if some users want to file their own tickets, it may make sense to make it available to them.

(It follows that the more complicated your ticketing system is, especially in the number of fields you have to fill in to make an initial report, the worst it is for users. Unless they are unusually interested in how your run the systems, they probably have no idea what the right answers are for all of those questions that they're being asked.)