I replaced the device when the battery was defective, 3 times. Then I bought the one from Philipps.

Yes, the service is offered by BBI. However, I am not convinced of the quality. The new battery lasted three months before it started to weaken. There is no guarantee on the service.

I have just had a battery exchange done at BBI. The current cost: Fr. 40.--.

I would try a small electronics shop. I changed the batteries myself. But you have to know how to solder.