Hello Kibris
If your complaint is still being assessed by an Adjudicator or been passed to an Ombudsman for a final decision, remind them of their statutory powers to request information.
http://www.legislation.gov.uk/ukpga/2000/8/section/231
231 Ombudsman’s power to require information.
(1)An ombudsman may, by notice in writing given to a party to a complaint, require that party—
(a)to provide specified information or information of a specified description; or
(b)to produce specified documents or documents of a specified description.
(2)The information or documents must be provided or produced—
(a)before the end of such reasonable period as may be specified; and
(b)in the case of information, in such manner or form as may be specified.
Regards
Ian