Rebismart - batteries

Hi guys

I’m brand new to the Rebismart device. The nurse came to teach me 2 days ago and today was the first time I did the injection myself. When I turned the device on today it asked for new batteries, though the batteries were brand new two days ago and I was told they’d last 1 year! Did this happen to anyone else? I’m worried my Rebismart device is faulty.

I replaced the batteries today and did the injection fine but it is a little worrying - what if this happens again on Sunday and I don’t have any other batteries as I’ve now used my spares :s