. Immediately interrupt the person in a friendly way and explain your problem.
2. Always try to make use of idioms such as: "Sorry, could you please spell that for me?" – don´t invent or try to create your own sentences.
3. Learn the English alphabet! There will always be a situation where you will have to spell a name or an address out loud.
4. And last but by no means not least: Keep it short and simple!
If you haven´t understood what the person at the other end of the line has just said, you can always politely interrupt them by saying:
Sorry, I didn´t (quite) catch that!
Excuse me, could you repeat that, please?
Sorry, my line isn't very clear, may I ask you to speak up, please?
Here are some other useful phrases for difficult situations:
Sorry, we got cut off (when you have to call again)
Sorry, I think you´ve dialled the wrong number.
Sorry, this is a really bad line – I´ll call you back!
If you have already spoken to the caller several times, he or she might start by asking: "How are you?" or "How are you doing?" As you know that this is a typical small talk situation, you answer:
I´m fine (even if you´re not), thank you. And how are you?
Not too bad. And yourself?
Can´t complain. How are things with you?
I´m very well, thank you. And how are you?
Some useful phrases to put somebody through:
Can you hold on a moment, please?
Please bear with me for a moment while I put you through.
I´ll see if Mrs Parsons is available.
Please hang on a second.
I´ll connect you to Sales.
I´ll connect you with Mr Garragher.
I´m putting you through to the marketing manager.
And you may end the phone call by saying:
It was nice talking to you, bye!
Have a nice day! Bye!
Talk to you again!
Speak to you soon!