You need to open up the phone and monkey around with the contacts to get them in the right spot so that they touch the transmitter when the shell is put back on. I find that just pulling out a hair on them usually is all that is needed. Take a look at the section on replacing a bad transmitter for pictures of what to look for. My phone miss-dials phone numbers. The Ericofon is a worldwide phone.
Some phone systems are more sensitive to dial speed than others.
Anyhow, frequently I have seen dials that are either turning too slowly or to quickly for the phone system they are being used on. My best advice is to experiment with speeding up and slowing down the governor. See the section on working on your phone to learn how to do this. Yes, just as soon as I get around to it. What I am going to cover here are things that will help sell your phone and avoid complaints.