I'm sorry to hear you are having a run of ill fortune. Leaving feedback is really your only venue for warning both ebay itself as a corporation as well as other buyers about the service and/or products you have received. Eventually, this will trigger internal alarms and the offending sellers will be hobbled. It doesn't appear, however, that what you are describing as an overwhelmingly poor experience is reflected by your feedback left for others. At a glance, I see some soft positives and two neutrals. Very few other buyers will take the time to read that.
In the long run, you might decide instead that buying domestically is worth the peace of mind.
Best of luck as you carry forward.