Ground rent charge increase after selling house.

2cats39

Hi,

I have been notified that I am in arrears of my ground rent charges. I have now sold this house and it was checked that I was up to date with these payments. However, my ground rent company has now been bought out and the new company has stated that my ground rent should have been reviewed when I bought the house 5 years prior and has backdated this so that I am now in arrears.
I cannot understand how this is legal or fair to charge this money now and since I have already sold the house the letter has gone to the new owner (who has then contacted me saying I need to pay 5 years worth of backdated ground rent).

What can I do? 

(apologies if this isn't quite the right place to put this, I am unsure which topic it should go in).
 Anyone got any advice?

Thanks

penners324

Do you still have the lease? Give it a read and find out the relevant clauses