Weak overreaction.

First, is it really that big a deal you got an email that looked like it was from someone personally but may have been automated (in fact you never proved that it was automated)?

Second, are you really that bothered that a company whose product is helpdesk ticketing software uses helpdesk ticketing software to manage customer correspondence?

Third, are you really that bothered by the informality of a web company?

The only mistake I saw here was using staff that are probably outsourced and certainly not native English speakers to handle sales questions.