I have been getting these nuisance calls daily at weird times. Sometimes its 11 in the night, sometimes its 6 in the morning. I pick up the phone and there is no response (not even a recorded cantonese message) . When I call back I get a dial tone. I have started keeping a list of the times called and the numbers. I found out that the first 6 digits of the number are same but the last 2 keep changing. I complained to my service provider PCCW, but they said they cannot do anything regarding this. Any suggestions as to how to stop these?