had power failure at the office and system not responding ie have to dial 9 for a dial tone but get message 'using CHG 1' then reverts to busy signal. However after several attempts to dial '9' by pressing 9 and speaker again and again ie on and off on and off -we get message 'using CHG 2' and we then get the dial tone. Also some incoming calls cutting off after two rings. Tried switching system on and off at mains but to no effect. Would appreciate some help if anyone has any. Thanks - Lynne