Yeung was given until Friday to prove he could raise the £35million necessary by the December 20 deadline set by Sullivan but failed to provide any assurances.
Sullivan said: "I would say the chances of the takeover going through now are no more than 10%.
"I have thought for many weeks now that it has been very unlikely to happen. I would like to pull the plug now because I am fed up with it.
"It is hard to contact Mr Yeung. He does not return calls or emails. He is very elusive."