I have a Salter Electronic Bathroom Scale. It just started turning on and off and not weighing properly; e.g., it weighed me at 1/2 of my actual weight. I tried taking the batteries out and putting them back, but that didn't make any difference. I tried putting new batteries in, but that didn't make any difference either. What should I do? When it turns on it sometimes shows 0.0 or other weights even though nothing is on the scale.