Here is where you had gone wrong like most people.
Shipping Process after 72 hrs does not mean it will be shipped within 72 hours, its another way of saying processing your order within 72 hours.
After that is when they will send out goods, it happens all over the globe.
With car parts and accessories it can take a while before a warehouse gets the goods to be shipped out, so they have to wait first for them to be delivered and then ship out to you, at that point is when your priority shipping comes into effect.
I am all for defending your consumer rights etc, but people do it for nothing, like possibly in this case you are thinking about trying to get extra when it is clear they have done nothing wrong yet.
I'm fine if I do not receive extra, an apology would be nice though. I just find it odd that as soon as I email the company about my product I receive a notice from the USPS.
I understand that a normal company who has thousands of car parts and accessories could take awhile. But this company only deals with a small specific type of accessories.
Though I am in the wrong because I realized they didn't not provide a estimated date of delivery. So I guess I will just keep my mouth shut and use this experience in the future to make better decisions.