Loan approved but must sell house rented out

App**** at Nedbank for a second home loan, as the first home is being rented out on a lease agreement. Part of the application was to provide proof of the lease agreement of AIDA that home is being rented out. Received AIP on 2 March with two conditions 1) valuation of new property 2) no negative credit info up until bond registered. I Paid deposit to attorney handling the transfer. Received a call from the bank to confirm. On Saturday afternoon received call from conveyancing attorney secretary advising that she has received instruction from bank, and asked whether I have sold my home yet. I advised that this was not a condition, it was not even in the offer to purchase - how can the bank impose such a fundamental change in condition. What about the tenant who signed a lease up to Dec 2015? Very confused and frustrated.