The Demon and His Viper Exclusive Edition

I paid in full for 3 box set. I get an email saying I didnt pay shipping for 2 of the box sets. I contacted customer support about the confusion. They said I needed to pay shipping for 3 boxes? I only paid for one. Went to their website saw shipping was not the same price I already paid. Shipping on their website is $13 something for each of the boxes I purchased. Since i paid more than that for shipping already; I asked if the difference would be discounted. I was told no shipping is calculated at checked out and is base off that. I explained I went to check out for each of those boxes and did the whole process and told them the shipping was $13 something for each box. Long story short they told me they would not be discounted the shipping price even thoguh they admit there was an error made online that let me pay for 3 boxes and 1 shipping fee. I will most likely be canceling this subscription soon.