there is power but the engine won't turn over, was running fine

Hello, If you have the dual "medium duty battery" option, you may have one that is not charging ,though the other should be able to crank the engine. Also, try starting in neutral instead of park, and listen for the fuel pump to see if it is priming, that is assuming that the engine is cranking and not starting. If the engine is not cranking, check the starter relay to see if it is clicking when you turn the key to start. Hopefully you don't have to tow it in for warranty work.