You should report overflowing bins to Torfaen Council, as they are highly likely to belong to them. Bins along a public highway form part of the highway regardless of the position of the post, so if it serves the highway but is on a post in our verge, that does not mean we empty it.
Things like bins and lights are there because of the footpath or road, so responsibility for these would rest with the owner of the street (highway) for example, a full bin in the street would be dealt with by the body with responsibility for the path or road. This is usually the Council. For more info and to report issues with TCBC litter bins Litter Bins | Torfaen County Borough Council
For more info and to report issues with TCBC litter bins Litter Bins | Torfaen County Borough Council