How long ago exactly was it sold?

If you have not sold in a while, there will be a 21 day hold as you are considered a  'new' seller

I am not a seller, so I am not sure if I understand the situation or your problem correctly, but if you registered for management payments, I have heard that the payment does not go to PayPal any more, even if the buyer used PayPal? Have you looked at your bank account?