How can I fix my 02851 model?

This watch has only been worn on odd occasions and was lying unused for quite some time. I eventually found someone to put in a new battery. However they would not attempt to set it up for me. I managed to do this myself as I had done when it 1st arrived because it was not set correctly then. I carried out everything to the instructions. Set the digi display etc. Then set the hands at 12 o clock. Left it to obtain the signal which it did. However the hands decided to stop later that day. I completed this all again three times. The last time I wore the watch for a full day and it was fine then after taking it off the hands had stopped the next day. The were not stopping at the same time either.Do you have an explanation for this please.