Also try these

Ticket Sales Office
Mr Giancarlo Duvis
Ticket Supervisor
Tel: (Direct) +974.440.9629
Operator: +974.440.9666
Fax: +974.483.2990
[email protected]

And

Qatar Tennis Federation
Khalifa International Tennis & Squash Complex
Al Majles Twaon Street, Al Dafna
PO Box 4959, Doha, Qatar
Tel: +974.440.9666 (Reception)
Fax: +974.483.2990

Best regards!!!!!!!