Black and Grey Tank valves stuck!! need help..

[Stangin]

I have a problem with my Mountaineer. I have been trying to open my BLACK water pull valve and it is stuck CLOSED. I have the same problem with my GREY water pull valve. Both of those valves are located in my convenience center. I tried heating the valves with a blow dryer, no luck there. I tried adding hot water to the tank to loosen up anything, no luck there. Added some lube on the pull valves, no luck there. I also added antifreeze, no luck there so far. Anyone have any similar issues with their Montana? Any ideas will be appreciated. Both tanks are already full so I cannot empty or use. I am beyond frustrated and need some help...