Hi,
I've been flying with Latam a lot the last two years and Delta has been generally adding my flights to my Skymiles account. Recently however they haven't gone through and its been a pain to get them added but I usually provide my receipt and boarding pass and it gets added. This latest one however, they are not with the exact same information and are requesting a ticket receipt with fare basis code. Unfortunately Latam can't provide this to me as my flight has passed. I find this absolutely ridiculous but I've spoken to two agents and requested this information online and been denied in all cases.

​​​​​Can anybody provide any insight or guidance? Maybe a fare basis code for Latam as well?
m