Pool Deals Refused to change my order Internet

I made a mistake in my order. I made the mistake of looking at a "special" that was advertised that day. When I went to check out, it only reflected my original purchase of a pool liner which is all I wanted. The checkout price reflected only this amount--so far, so good. However, after I made my payment, the total reflected both the "special" and the pool liner prices. I immediately emailed the company to have them negate the "special" from my order (it was a weekend and they could not be reached by phone) Two hours later I received an email that the order had already been shipped. The email also stated that the support center was closed and that my ticket would be addressed by staff as soon as they reopened. I called them the very next day. They stated that it was written in their policy online that all sales are final and that I can not return the unwanted pool pump back. I told the person that my ticket did not reflect the purchase price of the pool pump, only the pool liner, until I had paid for it. The entire affair ended rudely with the person stating that all sales are final.

     I have contacted my credit card company to stop the payment. They told me to send the package back unopened. The claim will likely be successfully disputed in my favor and payment will be denied. If not, I am well prepared to pursue litigation with this company. Their complete lack of ethics is very well documented by the BBB. They currently have 89 unresolved complaints against them on the BBB website, and the Internet is full of similar and much more nefarious instances   of this disreputable company's dealings with the public.