Originally Posted by Often1

If TK cancelled your original flight and you did not accept a reroute, you are entitled to a full refund under Section 8 of EC 261/2004 (non-EU carrier, departing the EU, which the UK still is for purposes of the Regulation and under UK domestic law). If TK has refused a refund and you paid with a credit card issued by a UK bank, this is an easy chargeback. Presuming that your reroute is at least partially on TK, do nothing until you have arrived. Then file a chargeback. Do it in writing (online is fine) and include with it: 1) a copy of your original e-ticket receipt; 2) the notice of cancellation or other evidence that the flight was cancelled by TK. 3) your request for a refund; and 4) TK's response. Make clear in your narrative that you did not accept a reroute of any kind. Be complete, stick to the relevant facts, and submit in an easy-to-understand way.

In general, if you reach someone who is self-evidently not understanding your situation or going down the wrong track, simply end the call politely and then call back. Keep trying until you reach someone who at least appears competent. Language barriers can be hard, but if you don't speak the carrier's language hopefully you know someone who does and whom you can do a three-way call with so that they can do the talking.