Freehold Fiasco

[Formidablelady]

We bought a Beazer/Persimmon home in June 2001 and paid £500 for the Freehold. We had a letter from a company called Leasehold Management Property last year informing us that they had bought the freehold interest from Persimmon on 5th July 2005 and that we owed them £350 ground rent.
We contacted our solicitors which were also used by Persimmon and they told us they could find no record of this and that the lady who dealt with it had left them.
We do have documentation from Persimmon however which says we did pay them. Persimmon have offered to refund us the £500 but I want the freehold which now costs £1995 + £200 administration fee and the £400 we have paid in ground rent.
If anyone has had a similar problem or can offer any advice we would be most grateful.