A BA customer helping a friend who flew AC.

Facts

Husband and wife purchased tickets using Avion rewards YVR to LIS return

Tickets AC114 TP260 TP259 TP8046
Received confirmation tickets booked and confirmed when purchased from RBC travel.

On return they tried to check in and could not.

Could not reach RBC travel or AC.

At airport advised wife's ticket fine but husband's ticket did not exist.

Had to purchase one way ticket LIS to YVR to fly with wife.

RBC travel and AC have ignored polite correspondence.

How to approach this? Appreciate help as I am BA savvy but AC ignorant.