I haven't read the other responses however this is how things typically work with respect to grants. When the project is completed the department or expert point person has to create a report on how the monies were spent, what were the outcomes of the project (especially how they matched with the proposal) and how the beneficiares benefited from the project. Monitoring and evaluation of the project by the expert should also be included. I like to add a section on "what could have been done differently" however not every one likes to add this in. Keep in mind that transparency is important and that funders know that things don't always work out.
As foundation grant writer, you then take the report and make it more reader friendly if necessary and send it on to your donor with a thank you letter.
With respect to your organization, they should have created a job description that outlined specifically what your responsibilities are as a volunteer or meagerly paid grant writer. Foundations personnell are fundraising experts, not researchers or experts on the work your organization does. While being well read on the subject is very important, we cannot be counted on as experts in any other field than fundraising or grant writing.
Very difficult situation.