While I wouldn't get all pissed off about not git'n paid right away, I WOULD get all bent outta shape about poor communications.
I resemble that remark
I have plenty of customers who I ignore emails, text messages, phone calls, and voice mails. Usually after I tell them it will be 6 months before I start on their job, and they call in 2 weeks to ask if I have completed it yet, or how is it going.
This is what I have experienced too. You need to find the person that speaks the language to make it happen.
Unfortunately that seems to be the case.
Here is a small lesson I learned through the experience. I learned that the reason my emails were not being responded to was due to having no "actionable" title. That is, the title did not explicitly say something needed done with the email, so nothing was going to be done.
The title of my emails started out as simply, "Invoice XXXXX", in which I asked about the unpaid invoice. I then added "Unpaid Invoice XXXXX". None of the emails with these titles received any response. My wife was kind enough to explain to me that the robots.... errr .... people who do this work, typically have their emails sorted. Key actionable terms in the title are sorted into actionable folders. They rarely if ever look at emails that are not in their actionable folders.
Her first email was titled:
ACTION REQUIRED: 2nd Request: Unpaid - Invoice XXXXX
and tada.... it received a response the same day.