Air India — Compaling regarding not clearing about luggage weight in the email sent after online check-in

I booked flight with Air India first time, It was a round trip. On 8th April i was flying from Delhi to Vancouver. I checked in Online, They sent me an email with a lot of information. There were two statements one was saying that luggage weight is allowed as stated in email while other was stating that weight of each bag should not exceed 32kg. But the thing is they have not mentioned that you have to pay extra or it is only for business class. It was really misleading information. When i reached air port they told me that weight is over. 5kg was over in each bag, was carrying no hand carry. when i showed them an email, they were silent was discussing with each other. then another lady came they were calling her Mam, She told that this is not for economy. When i asked her that why they have not mentioned business class or any other thing, she said that you are the first person asking this. at the end i paid them 20, 000 Indian currency for 10 kg even there was no handbag. That lady was really very disrespectful, She was not able to answer why they have not mentioned about over charge or business, she raised her volume.