Seller being annoying.

First time dealing with this, but a seller has decided to leave me on read after I disagreed with his counteroffer after I disputed an item they’d sent to me. It falls under the SNAD category with the size being inaccurate, more damage than stated etc.
If they’ve left me on read what do I do from here? (I am waiting to hear from support as originally I had been told their account was suspended, this was not true).