Terrible Reception in Tarzana, CA

In Tarzana, CA - (zip code 91356) south of Ventura Blvd., the reception is spotty at best. It has been this way for years and nothing has been done about it to improve reception.  I have even bought an M-Cell just to get service at my house and that only works after turning my phone off and on half the time to get it to connect.  The wifi-assisted calls are not much better.  Since we walk our dogs twice every day we have met most of our neighbors and they all have the same complaint.  The service in this area is terrible.  Also, we have asked them if they have ever reported this and they all say the same thing.  They have talked to people on the phone but it never really goes anywhere.  This entire area has bad service.  There are thousands of people that is affected by this. Sure, there are a lot of hills in this area, but something can be done.  I just want to make sure that someone knows about this and maybe someone can come out and survey the area.  Please help us get this right.  I was told by a neighbor that they have T-Mobile and they seem to be the only company that has service in this area.  I really do not want to have to change providers because I have a lot of business lines.  I get great service everywhere else except when I come home.