Personal Tax

I worked for an agency in 2006 and 2007 and they say they have not paid any tax but will not give me tax summarization forms

They say I only have to pay for 2008 but I believe under the bi-lateral tax agreement with the UK if one stays longer than 2 years then one must pay all back taxes which in my case includes 2006 and 2007.

I have no issue in paying the tax, I just want the agency to give me the forms as my previous employers have kindly accepted my requests and they were Government schools.

I do have all my salary statements from the agency but the Revenue Department will not accept them the statements or the contract.

I am happy to pay the tax and be responsible for it but I have hit a brick wall with the agency and the Revenue Department.

I will be leaving Thailand on the 23^rd March and really need to get all this sorted out by Friday 20^th March.

Please advise, thanks