They claim they are owed the money they put in + what it earned as an investment - what Albertan's collected.
They ignore that not all that money was invested, it was used for the intended purpose of paying pensions. They also ignore that not everyone who earned/payed in in Alberta retired there. How are they going to pay the pension of everyone who worked in Alberta during their career but retired to another province?
If every province used the same math to demand their share of the money there would be a massive hole in the budget. Their numbers do not add up.