Rainy

I have been trying to get through for about 3 weeks to no avail! Tried various times of the day & most of the time just get cut off after being in a queue for approx 45 mins. It's very frustrating that there doesn't seem to be any other way of contacting them. Does anyone know if I have been paying emergency tax through agency work if it will sort itself out automatically & I will be able to get a refund. No one has ever asked for my p45?