Mr Konstadin Michailov Kotirkov.
Speaks good English.
His adress: 2270 Bansko, G. Kovachev 6, Bulgaria (+359-7443-3544)
During winter time, he is usually found during the day around one of the ski pistes, but to call him before is the better option. If you want, he can arranges your ski equipment.
In the summer he also guides walks thrugh the pirin forest.