My original account contract with credit card was in 2001, the last activity on the account was in 2003. Does the SOL applies to my case ? And if it is applies so is it would be the old one (6 years from original contract?). Thanks so much.

In Ontario the limitation period for a cause of action that arose BEFORE January 2004 is six years.

The limitation period for a cause of action that arose AFTER January 2004 is two years.

If the last activity on your credit card was in 2003 then the six year limitation period would likely apply. An argument that the cause of action did not arise until 2004 could theoreticaly be made if the last activity on your credit card was near the end of 2003 (ie. November or December).