Using 150, I have tried at least 4 times during the last 6 weeks to get the number of rings increased to 10, before the answering service kicks in. On one occasion even a supervisor assured me it would be done, but there has been no change!
I am very pleased to report the phone is now ringing up to 10 times before the answering service kicks in. I don't know what you did, but thank you very much for resolving this issue. It's just a pity that Customer Services seemed unable to do what you have done.