How to handle an unjustified take down notice for my online store?

Can anyone help with this please? A few days ago I had a take-down notice for my store. I replied saying that I needed further explanation, since the theme in dispute had been bought in good faith and I had an invoice to prove it. They did not reply and took down my site anyway. I have sent futher communications including a counterclaim and a copy of the invoice for the theme, but no reply other than to say that if the claimant does not go to court our web site will be restored in early November (it has already been down a week). The business is losing sales and credibility and there is no apparent recourse. Other than leave Shopify, which will take some time, I do not know what to do.