my car was stolen...now the other insurance company which was involved in an accident while it was stolen are trying to contact

If your car was stolen, you should have reported it to the police.
Tell the insurance company that your car was stolen and tell them when and how you reported it to the police.
You are not responsible for the damages caused by the thief who stole your car (unless, possibly, you somehow were negligent in allowing it to be stolen -- such as leaving the keys in the ignition)

The insurer of the other car may think that you loaned the car to the driver who hit their insured. If that had been true, you could have statutory liability regardless of the fact you were not negligent. But it was NOT loaned, so you don't. You have to tell them that. If you did not report this theft, do it now and provide the insurer with the police report number. Go ahead and contact them. You do not sound like you have any liability, and you should tell them so.