Hi folks,
I'm going to try and keep this short, but succinct is not my strong suit.

Recently my company purchased some items from Company X. Company X requires payment up front, so I personally drove a company check to their office. When I arrived, the office lady said "Oh...ah...they actually said you need a cashier's check." This was 4:45 in the evening--the bank closes at 5--and the items were supposed to be picked up at 7am the next morning. So I have no idea how they expected me to produce a cashier's check.
The office lady then went and got one of the owners, Paul. Paul came into the office and introduced himself to me. He said that since we had a large order, he was wary of letting me pay by check. He then began a long and uncomfortable interrogation about my company's information, bank account, and financial status. He even asked me point-blank if the check was going to clear. He then said that he knew where to find me if the check did not clear.
Our company has bought from Company X at least twice before, paid by check both times, and not had any issue. Paul's interrogation was uncomfortable and, in my opinion, inappropriate. If he had any concerns, he should have voiced them in the two weeks prior, and if he was concerned about the check clearing, should have asked in advance for a cashier's check.
Upon relaying the story to my boss, she called our sales representative at Company X and basically said, "Why was my employee interrogated like this?" The sales rep apologized profusely and said that they had been having some problems with Paul. He then told my boss that she could send a written complaint to the other owners of Company X.
First of all, is this even worth filing a written complaint? My boss tends to be overprotective of the employees, and while I felt Paul was out of line, I'm not convinced it's worth complaining over.
Second, if it is worth filing a complaint, how should I write it? I don't remember the exact quotes of what Paul said--I was pretty floored at the time--but I do recall the gist of it. I'm concerned that a complaint would come across as whiny, and not be terribly effective if I don't remember his exact words.