To clear things up as it appears there is a misunderstanding somewhere.
As with any self-catering let, guests are fairly expected to leave the apartment in a reasonable condition. However, when rubbish is left scattered in each room of the apartment we cannot assume this to be a reasonable condition. Particularly when the fridge was full of left over food. What was left in the apartment amounted to two full bin bags of trash.
The laundry fee is for the laundering of the duvet which was used without the linen that was provided for the use of the airbed.
The charge we asked for was to cover the additional cleaning including collection of the rubbish from every room (including bathrooms), removal of the rubbish and the laundering of the duvet, not the linen.
AirBnB are currently investigating the claim, they have thus not supported either parties.