Hosts taking site offline because of problems

Have a pretty simple wordpress site. it is hosted with 123-reg in uk. It keeps getting put offline by the hosts because of problems. it looks like at some stage someone managed to get bogus posts installed. I subsequently removed the posts, updated all themes and plugins, ran wordfence and changed logins.
But again the hosts have taken it offline. I am prepared to completely delete all files from the site if that will achieve what is required.
The info I have from the hosts is that the main problem is that a script is running for more than 120 seconds and that script is wp-login.

They suggest adding something to the ini.php file saying max_execution_time = 120 but I’m not sure how or where to do that

Also they say there is daemon script – I don’t know if this is to do with the bogus posts (there have been no fresh bogus posts for a while)

They also say
“Also, there are daemon scripts running:
daemon | sweb14.hi.local: /usr/bin/perl as perl in /tmp”

I cannot find a tmp file in the root directory in file manager, other than that I don’t know what i’m looking for or how to deal with it.

So my simple questions are:
1. Is there an idiot proof way of dealing with this?
2. Would the easiest thing be to just delete all files from the hostng and start again?
3. Would that actually deal with the problem or could there be something hiding which I cant delete?

Thanks for looking!

PS the hosts have put the site back online for me to try to deal with but they have an automatic script which detects the “more than 120 seconds” problem and will at some stage take it offline again.