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I've never dealt with them, but I've seen others have success. Is it paid? Have you tried a GW?
If payment is required as a condition for mortgage approval and you cannot afford that amount, that raises a possible question in my mind as to debt to asset ratio....
You have cleared that hurdle with the lendor?
Did they say they would settle and remove for $800? You can continue to try to send PFD's and keep hoping for a new person, but that takes time. With you being a situation where you need it removed immediately you really are at their whim.