Property management company stress

Any landlords here with property sale experience involving a non responsive property management company who to date have not delivered a management pack and holding up exchange of contracts?
I’ve tried emails, phone calls on a daily basis, my solicitor has emailed them and still nothing despite numerous promises. Contract exchange date was 3 weeks ago but this didn’t phase them! They don’t return any calls and are non contactable the majority of the time.
Very stressful as I am concerned the buyer will walk away and I am still paying council tax and mortgage while all this drags on!
Any advice on how best to proceed much appreciated. Seems very unfair they can do this.
Thanks in advance
Rob

Have you paid their fee?

Yes, via my solicitors; £500 approx 4 weeks ago

I had a similar experience two years ago as a buyer of a 2 bed apartment built in 2019 and purchased in 2023. The property was advertised as having no ground rent. There was a whole load of confusion with the management company around the ground rent issue. Apparently the other leaseholders who bought from new were told the properties were exempt from ground rent. They were later told it was an error and then they were billed. Then some time later they were told that they were billed in error and then reimbursed. When I came to buy in 2023 the issue still hadn’t been resolved and it was delaying my purchase which took (10 months) the best part of a year. Apparently, some properties on the development were exempt from ground rent but not all. The other leaseholders asked which properties were actually exempt but they wouldn’t say. Our guess is that there are two blocks of flats that were designated for social housing and the exemption applied only to them.