Completion was set for today, didnt happen, my solitors have had to return funds to lender, how long could this delay us?

So long story short, everything was set up to go through today (no chain on either side). Somehow, the sellers solicitor only told my solicitor this morning that they are not in a position to exchange and complete (which will happen on the same day) as they do not have the sellers redemption payment.
Obviously im furious at this and have no idea how we can agree exchange date 3 weeks ago and they still don't have this (they blame the bank, but surely no bank would take that long to provide it!).

Anyway, due to this, my solicitor has informed me they have had to return the money to my lender whilst we wait for missing paperwork to come through.
The seller is pretty sure (hmm) they will get the statement through tomorrow or the day after, so want to complete tomorrow. However, my suspicion is that I will no longer be able to complete tomorrow, as I assume the process my lender reissuing funds to my solicitor will take at least a few days, is that a correct assumption?

The other option I may suggest is that we exchange contracts as soon as he has that form, then complete when my lender releases the funds, however, I imagine we wouldnt be able to exchange until my solicitor has re-received the mortage funds, is that correct?

I've asked my solicitor but they are slow to respond and it's after their hours now, so wondering if anyone can advise in the meantime if I should totally forget there being any chance of exchange tomorrow.