malware detected + cpu usage + access denied

[ Moved to the Fixing WordPress sub-forum. ]

Hello
Some days ago I got a warning from my host as follow:
“It has been reported that spam has been sent from your service to the highest number
Spamming from the website’s code is done by:
140047 cwd = / home / pazhuhes / public_html / wp-content / languages / themes
Due to this problem, the mail function is generally disabled on your host so you will not be able to use it to send email through the code. Most commonly used conventional CMS forms use the MAIL function to send mail, in which case these FORMs will now have a run-time problem. Basically, if infected on the host and INJECT of the infected files, it is recommended that the project be programmed and installed from the beginning, because the BACKDOOR is likely to be very high in the project place.
Therefore, you must submit to the code using phpmailer or PEAR or alternate strategies.

Due to the BERTINA host uses from CAGED FILESYSTEM for the CloudLinux operating system, the probability of occurrence of the server layer is 0%, and the only one is the problem, the failure to observe security policies, the use of plugin and cracked templates, and other similar items.
Please check and report the following:
If cms is used, is your cms updated to the latest version?
If you have used plugins or modules, have the items been zeroed and provided with the license. Or all of the free official plugins provided by your cms reference
Have all your plugins been upgraded to the latest version?”

And after some time the following warning:
“During the surveys done from the link below, your CPU usage rate is high and Malware is detected.This may have been due to penetration into your script or Cms.
Due to the importance of prioritizing the affairs of our users for preventing the disruption of your site, your site is now out of reach and this item is in the top priority and a description of your technical measures to investigate and prevent damage. Seriously post to your site on the Ticket.
Overuse of Cpu is done from the following URL:
Wp-content / languages / themes / txutwgbf.php ”
Please help me what shoud I do? How can I solve this problem?