General Discussion

Call the number on the back of your credit card, instead.

You asked how to tell the difference - and basically, you can't. So don't put yourself at risk by responding to ANY of them. You've lost nothing by calling the credit card company directly if it happens to be legitimate, and you don't accidentally provide information to scammers.

ANY contact initiated by text, phone, or email which is related to finances, or computer safety, should be ignored - unless you like playing with fire.