The factory serving failure is attributed to lesser serving methods that Excal is addressing at the moment. Your serving probably separated rather than wore out. Bob is right on about what to do and I am glad to see that I've helped someone.
I know how dusty it gets there. Lubing the serving will probably allow grit to embed and if your string rides on the rail it will wear the rail. If you leave it dry then your serving will abrade but you may get a respectable number of shots out of it. There is a dry lube meant for bicycle chains that may be worth a try. Looks like you will have to learn to reserve. The thread that Bob pointed out is a good start. Here's a link to a thread that shows you how to make a simple jig to help you reserve.
Have you asked the crossbow dealer in your state what they suggest? I think we'd all be interested in the answer.
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