Drew101

Hello there, I have a Kalkhoff Impulse Agattu C8 from 2012 and it has worked wonderfully. I took it in for a service and got a new chain and wheel true etc. When I got home there are 2 of the 3 blue charge indicator lights are flashing slowly on and off and the first light remains on. When I switch it off the lights return to three lit showing full charge. When I peddle at first there is no assistance and then the second two blue lights begin slowly flashing on and off and the first light is constant on. The assist kicks in then but it seems inconsistent. Does anyone know what this means? The cycle repair shop suggest that it is the battery but it seems a bit of a coincidence and the battery is showing a 40-50% capacity. Any help would be gratefully received. Thank you