By not paying you the interest which is not mentioned in the terms and conditions for issuing the credit card, you cannot hold the company responsible for your wrongful loss.
The credit card company or the bank cannot be sued for the wrongful loss which you have interpreted on your own concept which otherwise is not maintainable in law.
The law what you have mentioned is no where existing.
Do you have any evidence to prove that the credit card company has to pay you the interest for the amount held by them and what is the rate of interest.
You may sue them before a consumer forum for deficiency in service and also can seek compensation for the mental agony that was caused due to this.
If you are not satisfied with the opinions rendered, you may discuss at length on whatever points you ponder upon with your advocate in the local for initiating further legal action as desired.