I purchased an Eheim autofeeder about eight months ago. Lately, it has simply stopped working. It will not turn the barrel even when I push the EHeim button. The batteries are new. After it stops working, if I take the batteries out and then put them back in again, it will work correctly. However, when I check it the next day, it won't turn. I take the batteries out again, put them back, and it will work fine for the next several hours, but it still will not work the next day. Is there anything that I can do about this?