Tank Assembly problems of the 2007 Mercedes Benz E63

I purchased this car late July 2012 and when I went to pick it up I noticed a slight smell of gas from the left rear of car but, didn't think much of it as it was a new to me vehicle, just thought it was freshly filled up. The next time I filled up I noticed that the car smelled both inside the car and outside the car. As a new owner of a newer mb I joined mbworld form and searched this problem with e55 and E63 and found that it is a common problem for the w211 cars. Also, it seems the solution is not as obvious as one would think. On Nov 14, 20012 I took it to cal star motors in glendale CA (a mercedes dealer) for repair, they told me that the cause of the problem is the seal between the sending unit and the gas tank. They replaced this part and I drove the car home as I needed to bring in car with half a tank for repair I did not notice any issue. Next time I filled up there was no smell from inside cabin and only slight smell outside. I now have filled up several times and the problem has returned. I should say that after fill up there has never been any leaked gas present when parked as I check drive daily for any evidence of leaks in any fluid. I feel that if there is a gas leak issue with this/these cars which it appears there is based on so many issues reported that mercedes has a responsibility to solve the problem as it is a very dangerous situation to leave unresolved.

Fuel leak in the sending units, pumps and gas tank. Inside of car smells like raw fuel.