As frustrating as this situation must be, it's worth remembering that if you want good, efficient service and someone to complain to if you don't get it, buy new from a bike shop.
If you're looking to save money by buying used, remember that you're completely at risk of buying from someone who has a different view on what's acceptable practice when buying/selling.
Buying from the classifieds is a risk, one which can be mitigated to some extent, but a risk nonetheless, one you take to save cash. Keep some perspective when things don't go smoothly.
More than one person here has vouched for the character of the seller, he doesn't appear to be a scammer, so be wary of police involvement, you could cause a disproportionate level of harm over a set of handlebars
Honestly, I'm not sure what i would do in your shoes, but I do know it wouldn't be calling the police to report a crime
Could you imagine the police paying you and your family a visit over a set of handlebars you sold on STW?