San Francisco start-up Postmates describes itself as "everyone's favourite delivery service", but customer complaints are seemingly unwelcome.
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ValleyWag reports that Erin Boudreau, a resident of Seattle, emailed customer support with a complaint about her delivery experience.
As the email thread developed, founder and CEO Bastian Lehmann wrote: "Someone also please tell her to f*** off" — and the offending message wasn't wiped when the email landed in Ms Boudreau's inbox.
Understandably irate, she then took to Twitter, where she and Mr Lehmann exchanged messages.
In an apology on Postmates' blog, he claimed that his email "contained a bad joke which was very poor in taste" and said that it was a "major lapse in judgement" on his part.
Although she accepted his apology, Ms Boudreau isn't buying his excuse.