I have just purchased a S/H Lumix GX80 from a guy on eBay. In his listing he stated that the shutter count was approximately 2,500 activations. I have now received the camera, but on checking the Shutter Count myself it reveals only 29 activations! I am suspicious naturally and wonder if the counter has somehow been reset - is that possible? I would be grateful for your advice.
In a way, it might be possible to manipulate the shutter count on a camera, however this takes some technical expertise to do so.
There might be another, easier explanation: Most cameras do not count a photo taken with silent shutter as a shutter count. If the previous owner used that a lot, it might explain the low shutter count.
You can try that by taking down the shutter count, then take one photo with silent (or electronic) shutter and see if the count increases.
All of the things mentioned in this answer are certainly some of the possibilities.
Another slim possibility is that the camera has recently been to a Panasonic service facility and the shutter count could have been reset there using proprietary tools most manufacturers have for their cameras. Normally this would only happen if the shutter mechanism was replaced, but there may have been another legitimate reason to do it, or it may have even been an inadvertent action.