Yes, credit card companies can be our enemies, especially when they change limits and rates without any warning. Are you monitoring your credit, do you know if it improved at all when you paid down the credit card?
When calculating your credit score, they do take into account your credit available and your total amount owed. As long as you were making payments on time to that credit card, you might not be in as bad of shape as you thought. I would keep on eye on your score and see if it improves. Also, talk to the credit card company, they can be stubborn, but they can surprise you too and maybe get that limit back up.
If you have had late payments I suggest some credit restoration to remove them and improve your score that way. Keep an eye on your credit reports and look for any changes.
Good luck and I hope your score improves.