Suggestion or request......the result was the same and thats an unhappy customer.
I've never had anything like that written on a returned invoice. I make it a point to contact customers who are not on site and talk with them about what was done and why before I send an invoice. if I cant contact them I write an explanation on my invoice. Its part of what I call personal service.
Now if you dont like my advice I completely understand but be advised I dont have the problems your having and there is a reason.