Yes, if your site is Drupal or WordPress. I have recovered numerous sites in the past for clients who were in exactly the same situation. WordPress is notorious for being hijacked. This is generally due to bad maintenance but can be easily resolved. But don't worry, help is at hand.
What I’ll normally need to do is go through your code, database and running security tools, followed by re-instating your site on a new hosting service. I’ll sometimes recommend setting up a temporary holding page to limit your exposure.
Once it's fixed I will send you a follow-up report explaining my findings and the work I’ve done to fix the issues, along with a list of recommendations to prevent this from happening again.
Turn-around time is usually 1 to 5 working days and cost ranges from £800 to £2,000. This depends on the size of your site and how long it takes to investigate and safely re-instate.