opticsfast.com have threatened me on multiple accounts and have refused to return my items because of bad reviews i issued them.. Internet

I placed an order with opticsfast for chanel sunglasses when I received them they did not fit so I asked for a exchange. I was told they did not exchange and that I would pay a 20 percent restocked fee. I was not happy with this so we came to a agreement that I would order a new pair pay a ten percent restocked fee and send in a personal pair of sunglasses for a repair cost of 20.00. A month after having my glasses with no communication I called on them and was then sent a invoice 3 days later for 139.99. I asked for the repairs not to be made and for them to be returned. I then wrote negative reviews and then received emails where they threatened yo break my glasses then they said they lost them now they are saying they wont give back unfilled I take down reviews. Alexis palm coast