dvd-4-life

I keep losing the signal to certain channels and it has happened on more than one time.It usually happens on the weekend and they come back on Monday.I called the cable company(Charter)and did what they said and the channels still didn't come back in.They said it might be a line problem but I think all I need is a new cable box.Could there be some kind of electrical interference on the outside causing this problem?I am going to call them tomorrow and see if they will replace the box.