My Grandmother and her family were to be on the Titanic but missed their sailing so they got on the Ionian. Your relatives were on the Tunisian:

Name: Alb Mallard
Gender: Male
Age: 32
Estimated Birth Year: abt 1880
Date of Arrival: 27 May 1912
Vessel: Tunisian
Search Ship Database: View the 'Tunisian' in the 'Passenger Ships and Images' database
Port of Arrival: Quebec
Port of Departure: Liverpool, England
Roll: T-4786

Steve