It's unusual for GS and myself to agree on anything but I have to admit that there's probably a great deal of truth in what he/she writes.
A reference to the Law Society might be worthwhile but you'll probably get a much better response if your letter of complaint, to the firm of solicitors which has been inefficient, contains something like the following:
"Please note that, if I do not receive a satisfactory response to this letter, it is my intention to advise the media of the poor service provided by your company. In particular, please note that I have already drafted letters, expressing my concerns, for the attention of BBC TV's 'Watchdog' programme, Radio 4's 'You & Yours' programme and several national newspapers".
Chris