"Is there anyone else I can rereport this to?"
- NO! Of course not! - Why would anyone, or any organisation be interested?
Airbnb are not Best Western or any type of chain hotel with uniform standards. Airbnb are simply a booking platform. The quality of what you get varies enormously, from high end luxury to something SO simple & basic it would not be allowed on any other platform. ANYONE can list ANY place to sleep on the Airbnb platform.... (Of course places which every guest finds severely substandard would get such bad reviews, people would stop booking, and consistantly low rated places will be de-listed.) Did the place you booked have good reviews?
Airbnb started as a platform akin to sofa surfing when 2 flatmates had the idea of putting 3 airbeds in their living room, then got the idea of starting a platform where anyone anywhere in the world could rent out a 'space' in their home - might be a bedroom, might be a 'space' under the dining table!
Airbnb once had the slogan 'Live like a local!' - Not all 'locals' live in luxury, many live modestly, especially in developing countries!
And of course you get what you pay for.... If your mucky mattress experience was super cheap, then you can't expect hotel standards..... - Tho' I'm sure you'd find plenty of hotel mattresses like that or worse if you stripped the bed.....
Airbnb policy IS that you should notify them straight away if conditions are such that you can't bear to stay. Then Airbnb will find you an alternative place. - You spend the night; you are saying it's acceptable by doing that.
Toilet paper & towels are not standard in Airbnbs; in fact NOTHING is standard. You need to read the listing VERY carefully & check what is/is not provided, and ASK the host before booking if necessary. It's possible they normally provide towels & TP, but forgot, or were in the middle of some unexpected crisis....? Did you ask for towels/TP? - It's usual in Airbnbs to contact the host & ask if the host can sort out your problems before you complain to Airbnb.
One further thought re your being refused a refund: IF you could spend the night or several in an Airbnb and then receive a refund, well, what if EVERYONE did that? Made up some complaint?? I guess that's why Airbnb say to notify them as soon as something is not right, so they can re-house you?