Translation of Unterhändler

I will send you a summary of the activities from our last vacation last year, but I will be brief, so I will send only the highlights. It is best if we discuss everything, in the beginning of August.
I met the company last autumn, because the site's traffic is getting pretty big and they invited me to a workshop. They have convinced me that I have to put their logo at the top of the page to maximize exposure and this was a big mistake.
I've actually found Vocabulix only because I could not conjugate an English word and then I suddenly was there: learning vocabulary, and meeting friends makes so much fun ...