West Ham United director Karen Brady has slammed the incompetence of the LLDC.
The Hammers are involved in a serious row with the LLDC regarding the London Stadium where they play their games.
And now the club's vice-chairman Brady has accused their landlords of financial incompetence.
In her letter to Arbour, Brady wrote: "Firstly, the rent we pay was agreed following a competitive tender.
"Secondly, as Mr Hendy has now since kindly confirmed in his letter to you, we pay more than £2.5m by way of Usage Fee. Our rent is now £3m a year.
"Thirdly, the Usage Fee is just one component of the aggregate revenue and income earned by E20 Stadium LLP and the Operator derived from the playing of our home matches at the London Stadium.
"Fourthly, in our view (with many years of experience of operating a stadium behind us) we are staggered that the operating costs at the London Stadium exceed revenue. In our view, the actual elephant in the room is E20's failure to manage the operating costs competently.
"With everything we contribute factored in, the total revenues received by E20 from West Ham United and our activities is c. £10 million a year.
"The £6m of catering income, generated solely by West Ham United supporters, is the figure provided to us directly by our landlord.
"The distribution of this figure between the landlord and their agents is a matter for E20 so we are not in a position to explain why their return is so low."