That seems quite polite, actually. You didn't use the term "you dim-witted fuckers" once.I work in IT and my empathy has been pulled to it's absolute limit this week.
I wish I could respond with "Sir/ma'am, I wish I could help you more but I am writing these emails with as many layman's terms as I can. I have given you pictures. Please help me help you by giving me the laptop number I asked for in three prior emails across five days, thank you."