MSC so ***********

I booked my trip in April 2019 and they invoice us with a closing full payment to be done by 11/11/2019, which we did. on the 18 of December 2019 we received an email saying we owe an amount of 160 and when we follow up on that we were told that insurance have increase. what I don't understand is that when they do the issue out the quote the also calculate the unforeseen circumstances in terms of any port and charges that may occur including the insurance. how is this supposed to be my problem if the increase came after we paid the full amount, that is so very ***********. This is such a big company and they should know better. if the insurance when down where the gonna tell us.