Charge more

Asked quotation from courier guy, i made payment upon receiving the quote. the parcel was collected from seller and transported to el. i made inquiry about the parcel because the weight used to get the quote was more than the actual weight. i have asked the courier guy to review the quote. and they retaliated by adding kg on the items and telling me that i owe them. i dealt with Kezia Harris and Liezl Schultz they did not even acknowledge their wrong. the only thing they insisted was for me to pay because i did not declare all the parcel. they never sent me an adjusted invoice. i had to pay the extra R 540.70. The invoice from the seller show 200kg and courier guy say that the weight is 299 kg it is unlikely there can be 99kg difference. The parcel was collected on Friday and i got the invoice from courier guy today after disputing the R540.70. i had to pay it. they are unfair and not honest.