Re: Polish solicitor wants more money from me even though the purchase was unsucessfu
That's an entirely different set of issues from what you raised in your first post.
The big problem is that you are only dealing with this now. You should have dealt with those issues, and have complained to your solicitor, at the time.
I also think you're probably into the realm of needing professional legal advice here.
With that health warning, and on the strict understanding that I'm not a solicitor and not qualified to give the advice you probably need, what I'd do is the following:
1. Write to solicitor. Set out you concerns over the level of service. Be specific and don't use emotive language.
2. Ask for a breakdown of the work actually carried out by the solicitor on your behalf. Ask what proportion of the initially quoted fee (if any) was for outlays which have not been incurred since the transaction was not completed.
I would not start impugning his professional credentials - 1. because you should have checked that he was qualified in the first place, and 2. because attending college has no implication that he is not properly qualified unless there's a very great deal more to the story [could be anything from continuous professional development courses to taking a degree in nineteenth century russian literature in his spare time].
You can examine his response and take it from there. There may be a Polish equivalent of the Law Society to which you could complain - but given that you'll more than likely require professional translation services to take the matter further, it may well work out cheaper to pay him off and see an end to the whole thing. I suppose it depends on the amount of money involved and the risks you're prepared to take (exposure to equal or greater costs, possible credit rating impairment).