Suddently my product sale has been down to zero?

Hello my Best Support system sales rate goes to zero?
Please advice me what should I do?
All buyer emailed , and said it’s a top featured application. But why it is not selling good.
I want to know tips of this product marketing. I want to do paid marketing too if I get result.

Please please advice me.

Everyone’s item sales go to zero the second they’ve had a sale… until the moment they get another sale. It’s only an issue if it’s considerably longer, and/or consistently longer, to get that next sale than it was to get that last one.

You’ve had an average of about 20 sales a month since your item was released… how many sales have you had in August?

You updated the item in July… did you change any keywords, titles etc?

First of all thanks your valuable response. In August month sale is lower then other only 7. Yes in last update I have change the keyword cause I have add some big feature one of them is Wechat feature. I have just added a keyword of webchat and chat that it. Also added web chat in title.

Do you have any other suggestions?
I have seen in the analytics then view is very low.

Please advice me.