Hello all. Went to the complaining customer and made a test call to my customer. My customer has call screening on their voicemail. One of two problems occurred when the complaining customer placed a call. Problem one: when they heard the part of call screening that says "please record your name at the tone" , they began leaving their voicemail message (lenghty at times) and hung up. Problem two (and the big one for them), if they did indeed "record their name at the tone" and sat there, they experienced no ring back while the call was going through to the dialed extension. Complaining customer saw this as my system wasn't "seeing" aka "getting DTMF tones". Lastly, and this is funny. If complaining customer dialed an extension number and got the prompt from voicemail "you have entered an invalid extension" then complaining customer, again determined MY system was broken. This is their telephone systems coordinator no less. Resolution was to throughly educate complaining customer to stop, slow down and listen to all prompts and not to expect ringback. Advised my customer to provide an up to date extension list. Drove from Ft.Ld. to Orlando for all of this. Glad I wasn't paying for it. Thanks to everyone for your input.