This is a topic regrettably close to my heart, particularly since if you think you're calling Apple assistance in France, you often find that you're talking to somebody in Cork who'd be only too happy for you to speak English anyway. You can also find yourself being asked to hold, several times, and being flung back and forth from people in one country to another without knowing it unless you ask...
For such reasons, I've largely given up making such calls from home.
kelly's right about going up the chain, while beacher 's not alone in reminding us it can be just as bad in the United States: such tales know no borders.
A good perfidious stunt to pull, whether you work in the media or not, is to find out the name of the person in charge of media relations and/or marketing. This can easily be obtained from vendors, who know. Then you call that person directly and make the appropriate veiled threats regarding the lack of service and the company's reputation. This can often shift mountains. I'm afraid I've infrequently but successfully resorted to it when dealing with firms apart from Apple too.