See http://verizonmath.blogspot.com/2006/12/verizon-doesnt-know-... for a related horror story (Verizon and USA, but the basic point holds - you should understand what they really mean, and logic/reason holds no relevance!)
"Hello, could you tell me how much overage costs per MB?"
"The rates are very low, 0.10 eurocents."
"0.10 eurocents? Are you sure it's not 0.10 euros?"
"No, it's 0.10 eurocents."
"So 10 MB is one cent?"
"No, one euro."
"So it is 0.10 euro."
"No, 0.10 cents. Let's say 0.1 cents, for convenience."
"Okay, if it's 0.1 cents per MB, so 10 MB is 1 cent."
"No, 1 euro."
"But how can this be? 1 cent is already 0.01 euro, so 0.1 cents is 0.001 euro."
"Look, the rate is 0.10 eurocents. If you can't understand this, 10 MB is 1 euro."
"Okay, thanks. click"