Siemens is very territorial with regards to who is allowed to sell and where. If you want to maintain the site you may need to either mend the fences or find out who the regional supervisor is and see if (s)he will allow you to bend the rules.
After that, it's either a sharp learning curve ahead or you will need to find someone with prior experience.
If you look up the number online for the Buffalo Grove HQ I'm sure they can direct you to the best person to talk to.
Good luck!
Ken