Is is probable an oil change can be related to an oil seperator prob

What is your question?

Had my oil changed and after appx 100 mi road trip my car started smoking with heavy white smoke. I am being told the oil seperator went bad on car, however, it has nothing to do with having oil changed just 3 days prior! I had no indication of any problem with white smoke, prior to oil change. As soon as my engine light came on, I pulled over and parked the car. It has been towed back to Firestone who did oil change and now they "deny responsiblity" for my issue! My car just turned over to 72,000 mi after oil change. Should this defective oil seperator been detected during oil change? Appx how much will this cost to have oil seperator replaced by Porsche dealer?