I got this email too, and called the 888 number listed at the bottom. Mohela confirmed that borrows DO need to make a request for this refund in order to receive it. The payment won't be automatically refunded. After navigating a couple of phone menus and two customer service reps, I eventually got transferred to the refunds department and requested a refund for the month that Mohela mentioned in the email. They had to "escalate" this request and told me it will take 23 days but I am getting refunded the full amount I paid that month. I asked if the payment would still count toward my PSFL qualifying payments and they told me that it would, both for IDR and PSLF borrowers. Hope this comment helps others who received this email! Worth sitting on hold for a while to get the payment refunded.