My tank on my toilet will not refill. I have replaced the fill valvue and it was working but once the cold weather hit now it will not refill. It has been three days now. I have tried putting hot water in the tank and it might work for one flush but thats all. I have tried blowing a hair dryer on the water line into the toilet as well. No other lines in my house are like this, they all are working fine. It is just my upstairs toilet. Any ideas on what could be the problem? Please help!