ice in valleys caused damage to valley/roof pan joints

I thought I had all of my bases covered. I consulted here before having my roof installed. I am getting older and didn't want to have to roof rake my shingled house after every snow storm so I chose a metal roof which was installed in 2005. Now for my problem. I have 2 skylights. One, on the North side is above the entry way. I had a cricket type dormer (blind, dead space, framed on top of the roof and first layer of underlayment) installed over the door to divert rainfall and snow slide. Well, 2 1/2 years later I have the failure of the valley pan to dormer roof pan joints on both sides. It seems obvious that the skylights conduct heat to the outside. I knew that there would be snow melting as a result. I knew that ice would form. What I didn't know was that a metal roof wouldn't stand up to this situation. It seems that the installers should have been aware of this and made some structural provision for avoiding damage. I have contacted them and they blame me for not dealing with ice buildup. Isn't that why I got a metal roof, so I wouldn't have to deal with these issues and could stay off of my roof, either physically or with a roof rake or some other tool? They claim it was an act of nature and will be inspecting the damage so they can tell me how much it will cost me to have them fix it. Is this my fault? Should I really be up on my metal roof working on ice and risking that the whole snow load doesn't slide off and take me off my ladder with it? Do metal roof installers inform their customers of what they really will need to do when ice occurs or do they just wait for the damage and cash in on the repair job? Is there something the installer should have done but didn't, other than being completely informative about snow, ice, and maintenance? The first line on their web site home page is "Thank you for your interest in standing seam roofs. We appreciate the opportunity to provide you with one of the longest lasting and maintenance free roofs available today." This installer advertised a "Three year workmanship warranty". Do you think this should apply in my case? Please detail what type of repair would you recommend? I am attaching photos to assist you in answering all of my questions. Thank you for your expert opinions and advice. Brett