Seller not responding

I have used Fiverr numerous times and been very pleased til now. I had a brochure designed and I am generally happy with it, however, there were some typos that I wanted fixed. I sent him the request with the changes I needed but he did not respond until I messaged him again 5 days later. He did the changes immediately after that but one of the items was not changed and there was another typo on the revision, so I sent another msg detailing the typos. As of today, it has been 6 days since that last request and he has not answered. I tried to send him another msg today, but the system is not letting me send it...I hit the send button, but it just greys out and the msg is still in the editor window. I am sending these messages directly to his inbox, not the Gig communication page
Can a seller block messages from buyers?
I have contacted CS to see if they can contact the seller to resolve this.
Thanks for any help!
Joe