I added an article directory to my webhost, it had no much capacity nor bandwidth usage. but after two days, my hosting account has been deleted. I checked their privacy policies and couldn’t find anything against I have done.
is there any problem with article directories ?
it’s a non popular webhosting provider.
If they have a support ticket system, I would try submitting a support request via that if you haven’t already.
If still no reply, I’d just be taking my business elsewhere. 
Yes, if they dont care to reply then why wait? There are tons of providers who would be happy to be your host.
I suppose that is right time to find another provider. If they can’t explain you why your account was closed you need to find something else.
I would contact your hosting provider and ask them directly.
That means they’re not worth your business. The best thing to do would be to find a new provider with real support.
Jack
but after two days, my hosting account has been deleted. I checked their privacy policies and couldn’t find anything against I have done.
Are you sure that the two events are related?
In any case, a non-responsive host is something to avoid.
I did, but they didn’t reply.