Failure to live up Offer to Purchase

In the offer to purchase we agreed to take occupational rent until registration of the Bond. When the bank approved the bond we discovered the Seller had put a tenant in to rent the property even though the Offer to purchase stated that we would stay in the property until transfer. After this discovery the Realtor (21st Century Property Linksfield) assured us that we would be able to move in on the 15th December 2015 as they had sent a letter of eviction to the tenant. I then requested to speak to the branch manager and the office manager offered to resolve the issue by the 17th December 2015. On the 17th December I called the office and I was promised I could move in by the 28th December 2015. I called on the 24th of December 2015 to arrange the move to the property I was then given the date of the 30th December 2015. My lease expires on the 31 of December where I currently am staying I have no place to go after the 1st of January 2016.