Fuel leak

Replaced fuel pump in 03/08 because I could hear it "whining" and thought it was due to be replaced. Then, when car was driven short distance on hot day with less than 1/4 tank full, car would lose power, stall, then not start until engine/gas tank cooled down. Replaced this fuel pump 08/08 thinking it was not fully pressurized when tank was less than 1/4 full or that it was getting too hot without enough gas to cool the pump, therefore causing vapor issues. After the second fuel pump was put in, I went to the gas station to fill the tank-the tank filled up, then began to have a lot of overflow from the tank (not out of the spout into the tank, but somewhere underneath the car). Mechanic thought one of the hoses on top of the tank where the fuel pump is was not fully connected. Tank lowered out an in process, broke a valve on the new fuel pump which meant buying another fuel pump (this is my third in six months). Mechanic ensured hoses were securely fastened and problem was solved. Then took it to the gas station to fill it up and it leaked again from somewhere on the tank. Brought it back to the mechanic and he is not sure what is causing the problem but I am tired of paying $400.00 for fuel pumps. Car runs but at 1/2 tank the check engine light comes on and the code states it has something to do with the EVAP system. Any help would be appreciated. I feel like I am throwing money blindly at a problem and it is not getting resolved.