I just read the terms and agreement and apparently koodo can change your plan at will unless it has price guarantee. How do I tell if my plan has price guarantee? It's the $40/6gb promo from switching from PM to koodo.
Price guarantee = fixed term contract. Koodo does not offer such contracts any more, but also in practice has not increased the price of customer plans. Based on past actions, I would not worry about needing a Price Guarantee.