Our company website was set up using concrete 5. And we have had several issues with it including it being incredibly slow and constantly showing fatal error messages. I have tried to contact the developer several times but to no avail. I tried to do a back up to install the updates and I keep getting this message.

Fatal error: Maximum execution time of 60 seconds exceeded in /home/mastergr/public_html/concrete/libraries/backup.php on line 121

Is there a way to get the website fixed without the master files or are we stuck with this. I'm not really that savvy with code etc. so sorry if this seems like a silly question.