When you fill the the tank it will continually clicks off

most likely due to the tank not venting as it should. These have a fairly short filler neck and it runs almost vertical to the tank, so the filler neck and it's built in vent are rarely the problem. The vent to the evap canister and the vent from the canister to the air inlet however may be damaged or crimped, and the filters inside the canister may be plugged up or gas soaked. I'd start looking there, after checking the filler neck wasn't obstructed.