If you require a band score of 6.5 or above, you should really aim to get 10 out of 10 in Part 1 IELTS listening– as the questions only get harder in other sections (2,3,4). However, it can be surprisingly easy to make mistakes in this part if you are unprepared.
There are one or two points to consider when you are listening to a telephone number in English.
– 0 is pronounced “oh” and you are most unlikely to hear “zero”
– if there is a double number, we say “double 7”
– we don’t say the numbers one by one, rather we read them in groups of 2 or 3. So 13554684616 would be said “13-double 5 – 468-46-16”