Two years ago I was in negociations to buy a property being sold by Solvia.
The 'owner' was desperate to sell but the banks negociators kept stalling even though they had accepted my bid and I was keen to buy as soon as possible.
I believe the bank felt that there was no hurry and prices were likely to go up. In any case there was no further loss to them just less remaining for their client. They had no interest to sell as long as the original buyer had some equity left.
In the end I bought a similar property at the same price.
The moral of this story is that, if you cannot afford to continue to pay the mortgage, you should conclude a fire sale and accept your loss. Do not dump it on the bank.
If you are buying make your offer conditional on quick conclusion.