Experian-At The End of My Rope

I am at the end of my rope with Experian.

I recently settled with a CA who agreed to delete the three negative trade lines they were reporting to EQ, EX, and TU. They could not validate the debt as mine, and agreed to remove in order to avoid suit. They provided me with copies of their communications (Universal Data Forms) with the three CRA's and a letter to me acknowledging the dates and times they requested deletion of the trade lines.

EQ and TU promptly deleted the trade lines.

Experian has simply refused to delete. I just called them and they say the accounts are 'under investigation'. I asked as to what is there to investigate, since the subscriber themselves had requested the trade lines be deleted. I have sent them copies of the Universal Data Forms as well as a copy of the letter sent to me by the CA acknowledging these accounts were not mine.

I fully intend to file suit on Monday against Experian. Any one have any ideas as to what other approach I might now take to get these trade lines deleted?

So far I have...
1) Disputed the trade lines as 'not mine' on two different occassions. Both times these came back as verified.
2) Requested a description of procedures on both dispute requests, which I was not provided on either request.
3) Sent Experian a demand for removal letter, accompanied with a copy of the Universal Data Forms and a copy of the CA's letter.

Thanks,

MrKee