If they said they can fix from their house they are most likely using remote desktop features. This may allow them access to everything on the computer. You do not know what they may have left behind for applications. To turn off the remote access try this. Open System and Security. Choose System in the right panel. Select Remote Settings from the left pane to open the System Properties dialog box for the Remote tab. Click Don’t Allow Connections to This Computer and then click OK.
I would also change any passwords you may be using that came with the computer. Run an anti-virus program that may look for malware or a key-logger.