If you are being called by Capital One they are NOT breaking any laws. The law you are referring to is the Fair Debt Collection Practices Act(FDCPA). However, this applies ONLY to third party collection agencies and not original creditors. The next question is are you actually talking to them or just not picking up? Because if you are not picking up, then you are not talking to them. So they will continue to try and contact you until you do. By the way if you tell them you are going to sue them for these violations they will tell you the same thing. If you do actually file they will "counter" by filing a suit against you for the debt. As a reference Capital One is a company that tends to be very aggressive in filing suits. Since they can also use the Small Claims process there is no minimum amount your debt has to be. That suit will include the full amount plus court and attorney fees, which can easily add several hundred dollars. Since it appears to be a fairly new debt with recent "payment" history you have a very good chance of losing.
Now there is a bit of a caveat in your case, as it appears you are in CA. So you have an extra protection known as the "Rosenthal Fair Debt Collection Practices Act". Which basically extends out the same rights of the FDCPA for Original Creditors. However, you still have to notify them that you do not want them to contact you.
As to what you are paying. If you are not paying the minimum they require then honestly you might as well not pay anything(IMO). Because you are probably not even covering the interest and late fees, and since you are not paying as agreed they can still turn you over to collections and report you as late on your credit reports. You can then save that money and hopefully get them to accept a bulk payment before they charge-off the account.
Now, I will tell you that Credit Card companies are not as evil as you may think, and the reality is they did not force you to use your card. If you are having trouble they may work with you. It's not guaranteed by any means. However, if you don't talk to them at all what are they supposed to think?