Someone hacked into my yahoo account?

i received a email to my other email adres texduvenhage@yahoo.co.uk stating that they will close my account if i dont reply due to unused yahoo accounts YES i did now i canot open that account anymore and they sending letters so far to all my adress contacts and asking for 950.00 pounds. please help i need to open that account for work stuff. thank you reply to tex.duvenhage@yahoo.co.uk