Site is down (hosting is going out of memory)

I am getting HTTP 500 ERROR on both the front-end and the admin on a site hosted at WPMU DEV.

I contacted you a few days ago and first the problem was related to a memory issue and it was fixed by the Hosting team.

But then the issue reappeared, so I contacted you again and I was informed that there were some files infected on the site.

The WP core files had been replaced and that it was working fine already, but it went down again after some min and I keep having outages.