Does your PS4 sound like a jet engine? Does it show you the overheating screen? Thats likely caused by a build of dust over time in the system, completely clogging up the cooling system. This kind of repair is something we do regularly here, and is likely our most popular job. We're experts at sorting this issue.
Even if your issue isnt related to overheating, we can still help. Maybe your PS4 randomly turns off, or do games just disappear. Perhaps you can only get it to start in safe mode. Just speak to us via facebook, or our email (email@example.com) and we'll get it sorted.