[xethos]

You didn't say, and I wouldn't want to assume the situation, but calling the number on the back of a bank or credit card would work better here (in case it was a bank). This is also an argument in favour of paper bills, or logging in to a customer portal as a best-of-the-worst option

[Neywiny]

Correct. We all told the person after that they should've called the number from previous communications. But there's so much diligence that's needed in these stressful times and it only takes one mistake to get fooled. Wasn't nearly as bad as this though...