Shall we change the web host?

Since last year, the keywords of our website has reached good rank in Google, Baidu and Yahoo, for example, the keywords custom makeup brushes and makeup brush factory has ranked the first place on the first page, the keyword makeup brush manufacturer also ranks in the first 3 place, which helps us a lot on our marketing. We can receive new inquiries every day from international customers.

Although we are Chinese makeup brush manufacturer, to explore more international customers, we bought our web host in USA, which can ensure that the international customers can open our website quickly.

However, since last month, our website had some problem: sometimes, we can not open the website; sometimes the website works very slowly. Many customers sent us emails to complain that they could not open the website; ourselves also have problem in opening our website. And after checking, we are surprised that all our keywords’ rank sharply dropped, none of them could be found on the first page of any search engine.

We have discussed with our server on such problems for many time but no solution. Now we are considering changing another web host which can be more stable and work better. However, we are not so familiar with such field and some guys said that changing web host may also cause the rank drop of our keywords.

What shall we do? If not change the host, our customers can not normally visit our site and the keywords rank will keep dropping; if change the host, which one should we choose?