No response to tickets raised

I have raised two support tickets against the NA support centre from the beginning of June, and have not even received an acknowledgement that the tickets have been registered. As a NZ based player my default support centre is EU, and so I raised 2 (different) tickets with them only to have them immediately respond and advise that I need to contact the NA centre as the issue involves an item purchased with US dollars (the 2nd ticket was raised in error against EU as it is my default but there's nothing on the submit site to tell you what centre you are logging against). The EU support centre have been great at responding, but the NA Centre hasn't even bothered to acknowledge my tickets. What is going on there? When can I expect a response?