Originally Posted by durberville

Not totally correct. A significant question when determining the meaning of a contractual relationship is 'what were the reasonable expectations of the parties when the contract was entered into?'

In this case, it could be argued that consistent prior conduct contributed to reasonable expectations. Regardless, the weight of evidence even without prior conduct is sufficiently compelling: a written statement by an agent of the corporation; the fact that the Ameriprise and regular platinum look physically different; the fact that the names of the cards are different; the fact that points were awarded and then taken away, and; the fact that the Ameriprise card can't be accessed on the regular Amex website.

If you want to argue that there's sufficient ambiguity or leniency in the terms to allow for Amex's interpretation, you have to remember the rule of contra proferentem, that where there is ambiguity in a contract of adhesion (such as a credit agreement), that ambiguity must be read in favour of the person who did not draft the contract. So unless Amex expressly states that the Ameriprise card is the same product, any reading would be relying on ambiguous terms, which would have to be read in my favour.