I can't use my phone in the Super WalMart nearest to my home. The Sprint signal will not stay in. When I put the phone on automatic roam, the Sprint signal just keeps going in and out. I can't place a phone call from that particular store. I get good reception almost everywhere else. I did have trouble with reception in one of the local malls. But I was able to place a phone call after I put the phone on roam. Is there any way to force the Sanyo PM8200 to stay on roam so that I can place a call in areas where the Sprint signal is weak?