Question

Credit card companies track your transactions. how can they abuse this?

Answer 1

Answer:
Credit card companies can invade your privacy by monitoring all your credit card transactions and making decisions, whether correct or incorrect, about your credit worthiness and your character.

Explanations:
All credit card transactions are logged into a data base which is accessible to credit card companies. 
Therefore credit card companies can form opinions about your credit worthiness on the basis of your credit card transactions.

For example, if you use your credit card to pay for groceries, utilities, and ordinary bills, a credit card company could assume that you are in financial distress and make a decision to reduce your credit limit.
If a person uses a credit card often at a casino or gambling locations, that could also signify to credit card issuers that the person may not be using money wisely, and may not be willing to provide more credit to the gambler.

To sum it up, personal privacy is lost whenever a person uses a credit card. Credit card issuers may form opinions about a card holder that may be correct or incorrect, based on the person's credit card transactions.