OPticsfast Deceptive marketing - dont even inquire Brooklyn, NY Internet

I inquired about getting a repair to a pair of sunglasses online from this company Optics Fast 

They advertise FREE shipping labels on their site. I just needed a small screw and thought they would estimate online for me.  It became clear that they would not do that but would send a label that I could you use to send them the glasses.  I became nervous that they would have my glasses and would try to tell me it was going to cost $50 or something to replace the small screw and they would have my glasses.  

So I advised them that I would not be using their service and they then said I owed them $ 5.49 for the shipping label . I offered to send them back the label.   Now they are threatening to turn it over to  collection agency even though I have made it very clear I will not be paying this, as I consider it extortion.  They have sent me a number of harassing texts and have called me on my cell phone.  

You should not even fill out the enquiry form because they then say you have "entered into a contract with them"  which is the most ridiculous thing I have ever heard of.