As HH:
I will ask a senior for help. If there is no senior there to help
me, I will ask the customer if I have understood correctly. I
may ask the customer, especially an Indian, to speak slowly.
It is because of their accents and they speak very fast. I
will also guess from his / her body language or ask the
customers to write down their needs on paper. This works well
for me although it is time-consuming.