Our Avaya Partner ACS phone system is about 25 years old (we're a non-profit). All phone lines blink red when we receive a call. If we don't answer immediately, it sends the call to the main voicemail (the greeting no longer comes on). If we answer the call in time, it says "goodbye" and the caller is usually still on the line. I'm looking for someone who can diagnose these issues. Any help is appreciated.