Giving customer access to their Work PC from home

Hi Guys,

I have a client who would like to access thier work pc from their home. I have given them the teamview Number and i have setup a second password for them. but the only way i can see them using it, it give the access to my Teamview host, meaning that they are able to see ALL my customers. so I realise i have done something wrong, which version of teamviewer to i need to install "personal or Commerial" or this not allowed. ?