Double payment - Frustrated!

In November of 2025, a double payment was made to my student loans. I requested the set up of an auto payment and in the past it took several months for it to get set up so I assumed the same would happen this time so I made a manual payment so I wasn’t late. Both the auto payment and my manual payment were made. I immediately asked for a refund of one of the payments. I was told it would take up to 90 business days. That brings us to April 2026 and I still have not received my refund. I looked up where I could send a complaint and did so through the Federal Student Aid website on June 2nd. I was told I would have a response within 15 days and here we are, almost a month later with no response. Has anyone else dealt with this? This wasn’t a small payment - $890!!