In short, you shouldn't need to assign a POA to a solicitor that generally does work for your complex, you would just need to intruct them to take the legal action on your behalf. You would, however, need to provide evidence to show that you had made reasonable attempts to collect the outstanding debt.
We drafted a couple of letters, one gives 30 days to cough up (or provide reasons why the debt isn't due) & if that doesn't work, we follow up with another giving 7 days (again giving option of providing reasons why the debt isn't due). Both of these letters we had translated & are sent the equivalent of recorded delivery, which I believe is called "mutlu post", so we have certificates of posting. An emails trail may suffice, but we have never used this method.
The last time we needed to use court action was about 2.5years ago when the court fee was 50tl & the solicitor's costs, which are listed in their "bible", were 17% of the amount being pursued