Symfony websites need fixing as being used for spamming

We have been trying to fix a couple of sites built using Symfony (PHP), which have been taken down from our servers due to them being used for spamming. We had a guy look at them for us, but he has been unable to get rid of the spammers code, so therefore we are back to square one. Would this be something that you would be able to help us out with? The sites have been down for a few weeks now, so it’s pretty urgent that we get them up and running by tomorrow (1st August).

If you are able to look in to this for us, I will send over the ftp details and relevant files.