@Alla31 I would check the prices in your area and see where you fall, maybe you should lower your price for a couple of months to get some more reviews. Also, as @Mandy81 says, there is nothing wrong, IMO, with asking for a review.
I thought your response to the bad review was MUCH too long. You want to keep it to one paragraph at most. I also would not feel comfortable not flushing toilet paper, that is weird. I understand that guests might cause plumbing problems, but I don't think the answer is to store all the bodily waste tp in the bin.
Also, there is no need to list every single thing in the unit in the description.
If you are really a ten minute walk to the beach I would add a beach photo and put in the caption that you are a ten minute walk. That alone will motivate people to want to book your place.