Property Law Question
I recently concluded a private purchase of a property which I have been renting for the last six years.

The lease agreement states that if the property is sold by the owner to the tenant within six months of the expiration of the lease or during the currency of the lease and exclude the agent from the transaction, then any monies held by the agent (ie deposit) will be retained by the agent pending the outcome of the dispute. I did not remember this part of the agreement, and it would appear, neither did the owner.

On four separate occassions I expressed an interest to the agent that I would be interested in purchasing the property, which I knew the owner wanted to sell, but not at the price the owner was asking for. I never heard anything further from the agent and he certainly did not remind me of the clause stating that he should be party to any transaction.

In March 2012 the owner contacted me to find out whether she would be able to arrange for a potential buyer to view the property, at which time I told the owner 'you do know I'd be interested in buying the property don't you? But not for nearly the amount you want'. She said she was not aware of this and asked what I would be prepared to pay and I told her. She said that if I was serious, we should talk. I set up a meeting with her and the property was sold to me. Yay me.

On 04 April and 05 April the (previous) owner and I respectively received very, very aggressive and abusive calls from the agent threatening to sue us for his lost commission. The agent has since gone from threatening to sue the owner to now threatening to sue me for his dratted lost commission. To add insult to injury he has maligned my character.

The (previous) owner forwarded me an email today which the agent had sent to her husband (the owner now refuses to deal with the agent because of his aggressive and abusive behaviour toward her). The email contains a number of untruths, maligns my character and, to my mind, intimates that the owner should sue me for the agents commission and that the agent would be happy to take me to court because he's so confident of his facts.

My understanding is that a) an agent (he's a rental and real estate agent) is obliged to present all offers of interest to a seller and b) a seller is liable to pay the agents commission.

I have refused to take any of his calls (I've just ignored them and the (previous) owner also advised me to ignore them). So my question is:
What rights do I have?
Can I be sued for the agents commission?
What should I do? In regards XXXXX XXXXX latest email, I have drafted a response to the (previous) owner to the effect that I'm not going to respond to the agent's email, suffice to say it contains a number of untruths. I've said that I would be willing to help the (previous) owner but that I would not be prepared to deal with the agent and that if he wanted to speak with me, then he should do so in writing and I would respond accordingly.
What actions can the agent and/or the (previous) owner take against me?
Should I hire a lawyer or should I play the 'wait and see' game?

Regards
Lindsey

Optional Information:
Province: Gauteng

Already Tried:
I've spoken to our in-house legal advisors, but I'm looking for a second, and possibly a third opinion.