Payment reversal

My brother paid money into my account using my old cell phone number, now that money is hanging there and we ave been trying to get them to reverse it for the past 5 months now, every time they send us a reversal form that we need to fill in and still nothing happens. They told us that if the money doesn't clear within 30 days it will automatically reverse back, but then still nothing happened. I think that this is very poor service...