Answer and explanation:
Advantages of telephone interviews:
They are more convenient than face to face interviews
They are alot more cost-effective
There is a wider geographical access as you can reach people in other countries too
Disadvantages of telephone interviews:
Questions become has limited complexity as opposed to face to face interviews
It may be somewhat intrusive for customers and there could also be interference from noise in the background. Also bad connection issues.
Advantages of internet survey:
Increased geographical access leading to high response rate.
Alot more convenient and flexible than face to face interviews
Low cost advantages
Disadvantages of internet survey:
Inability for individuals who are not online to participate
Non response bias
Limited complexity of questions, usually close ended questions