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In all honesty, the only responsible advice I can give you is to upgrade your site to the latest published Joomla! version (3.8.2 at the time of this writing).

Your very old version of Joomla! has a lot of known security issues. The last version of Admin Tools ever published for Joomla! 2.5 covers most, but not all, of the known security issues.

Moreover, your problem seems to be that your site is already compromised and the hacker has created spam pages on it. Even if you delete them, they will abuse the same vulnerability to get right back into your site and do the same thing again.

At this point your site is compromised and beyond fixing. Using a different kind of extension, preferably a supported one (e.g SobiPro), to rebuild its functionality on top of a supported version of Joomla! seems to be the only responsible thing to do. Anything else would be a lot of work for just temporary relief until your site is hacked again, because of the same or a different unpatched vulnerability in your very old software.

I know that rebuilding sites sucks. I know you'd much rather do something more productive. I have done that many times with our site. It's part of the necessary cost to maintain a non-static site. I know that it's a bit late now, but next time try to be proactive. If the software you are using is no longer maintained (like the job board component you have) or reaches end of life (like Joomla! 2.5) you should start planning the migration as soon as you find out that the software you're using is becoming obsolete. Don't wait five years until your site is thoroughly hacked. Save yourself some stress, frustration, time and money by being proactive. This wisdom tidbit is brought to you by experience, especially the one gained the hard way ;)