Can your credit card company increase your limit without contacting you?

yep, they want you to spend spend spend, on the flip side it is a good indication your cridit score went up.

Yes. They do it all the time to customers that always pay on time. They often do it at holiday time to try yo get you to spend more. Don't charge more than you can afford payments for. Just because you have a $500 limit doesn't mean you have to use it.

yes this is normal if they do this I could call them and try to lower your rate because that means your credit rating went up, if they do not lower your rate and you are paying a annual fee I would find a credit card that will give me a lower rate and not pay an annual fee, check out www.fastcreditcardapprovals.com here you will be able to compare all major credit cards on rates and rewards.

Sure it is. You're a "good customer". Let me define this for you:

1) You have paid a bill, maybe even on time

2) You bought something rather expensive. They like this.

Cancel the card account. Cash is king. Credit is synonymous with "I cant afford this".

Yes, and if you didn't request it and don't want it contact them and tell them to restore it to the previous limit.

They have to abide by that.

They do this because usually people don't pay attention or they like having the increase. But you don't have to accept it.

Yes, although they usually send you a letter after the fact.

They`r always wanting you to get further in debt

What grounds do you intend to sue on? The creditors always have the right to close the account. "Unfair" does not mean illegal.

This is very common. They would love for you to go into even more debt.