Some portion of legit call centres for banks or telcos (as an example) have an accent, especially when support services are outsourced. Means that many are not deterred by an accent or imperfect email phrasing when approached.

In one case of a friend's mother being scammed: she'd complained to her ISP about an issue with their service. Their actual customer support told her to expect a call back later that day. Then some sort of Microsoft support scam out of India happened to call her an hour or two later...