Sanyo phone cutting off

Question

I have a sanyo scp-200 model phone and over the past couple of days the phone has been totally cutting off. It only does this when I am on a call. I can leave it on all day and it does not do this. I can text people without this problem. If I try to call the person back when the phone cuts back on I usually can talk to them maybe 2 minutes and then same thing.