Hi I am a new member,I have just purchased a 2011 A3 Sportback,the offside rear brake lights only outer one working,and the nearside rear brakelights only inner one working ? ( 2 bulbs in each)

I have taken the lamps out and fitted new bulbs still not working ? why is one bulb in holders working and not others?

The nearside reverse lamp same story tested bulb is ok but not working please help any advice.
Thanks