Thanks for the info.

I had a good reason to worry. I called LATAM and have been told that DL " pulled " the LIM-BOG ticket from their system. Which would explain why my seat is shown as available in the seat map.

DL told me everything is fine on their end in the past.

Will try them again.

One good thing is that Canadian passenger protection law applies to the whole journey as I purchased a fare from Columbia to Canada on one ticket, therefore DL as the issuer is responsible for providing the service paid.

I hope they can figure this out soon since Air Canada may go on strike soon and all other airlines will fill up their seats to Canada if that happens.