What happened to you is known here at the MyFICO forums as balance chasing. Pretty much every lender will take this type of action if they feel they are at risk. I'd say it is a fortunate mistake that you came to these forums to complain but might actually learn something about how credit card issuers work that could help you in the future.
There are a number of things that negatively impact your credit. People like to focus on inquiries but thes have relatively small impact. Obviously missing payments and defaulting are huge factors, but they are not the only things. After missing payments, maxing out cards and available credit are among the riskiest bahaviors from the persepctive of the lender. This is appears to be the first gap in your knowledge because you focus on the fact that you never missed any payments (good), but gloss over the fact that you had really high utilization for a really long time (risky).
The second thing you seem to be confused about is that they should have communicated with you before decreasing your credit limit. That is something that lenders (all lenders, not just commenity) will never do. If they spot risky behavior, the last thing they want to do is to alert a borrower that they look risky - that would just prompt a borrower who actually is at risk to max out their limits. What lenders actually do is balance chase, reduce limits and/or close accounts to minimize their risk. All lenders do this, though each will become skittish about different activities.
Based on your story, I'm going to guess that you have little to no other available credit; so either this Total Rewards card is your only card, or if you have other cards they are already maxed out. This means that your utilization has been through the roof for a really long time. If you do in fact have other cards, what you really need to worry about is your other lenders taking action against you at the first opportunity. And let's be honest, if you need to max out all of your available credit for a vacation, they are probably saving you from yourself.
Here's some general credit advice that's pretty common around these forums. Never miss a payment and pay in full every month if you can. If you're not able to do that keep your utilization below 10% on each card if possible and if you're not able to do that then under 30%. Diversify your accounts with many different lenders.
@Anonymous wrote:I agree! Do not do business with these people. They have no customer relations at all. You will never get a finance charge removed for any reason whatsoever. They are the worst to deal with. Move on there are friendlier business out there.
You may want to note that most (if not all) credit card companies charge finance charges, and very few will remove them without a good reason--those who do will usually do it automatically (i.e. if you pay on the statement processing date).
Every single bank and credit card company on the planet has plenty of people who will say they suck, they're evil, they're "the worst to deal with," etc.
And any credit card issuer can, and has the right under the contract you signed to get the card to, increase or decrease your credit limit and cash advance limit, close your account, place limits, refuse charges, charge interest and fees as disclosed in their T&C, etc. Few banks or even credit unions will pursue "friendliness" over financial stability and even profits. If you find one who does, let people know. 
