I suppose they could buy...
... a few Falcon 9s and the requisite training from SpaceX. I don't know how long they can just stand there, unfueled, and still be ready to use, but SpaceX seem to have roll out to pad, fuel up and launch down a very short time nowadays. Of course, that requires all the attendant infrastructure and there may be a lot more going on in the background for weeks or months before a specific launch that I'm not aware of. I don't believe there are any other suppliers out there capable of providing a launch more or less on demand unless notified well in advance to maintain a "hot stand-by" at great expense.