I don't expect BestChange to do this. They are a well-established company and have a very good reputation in and outside the forum, but you may not have met the requirements for the claim as in the quote:
Not really, just look at the following website:
https://antiswap.info/, we could write a whole topic on the malpractices encouraged by BestChange...
Didn't you read the rules? It is clearly written on their website that they have the right to request a verification, which will also allow for AML and KYC verification. It is also clearly written there: "The ImExchanger service will not enter into business relations with a user suspected of or directly related to money laundering or with a person whose funds were obtained as a result of illegal activity."
If you decided to contact them, then you had to agree to their terms.
In addition, the exchange aggregator BestChange has a paid service, for a ridiculous price, where you could pre-check your funds and decide whether you should exchange or not.
An unregistered company has no right or legitimacy to request, process or store personal documents or sources of funds info. An unregistered company has no lessons to teach to anyone about the respect of laws/regulations, they cannot pretend to be subject to any regulation, and should return frozen funds if they refuse to process them. When they never return the funds using KYC requests and various (impossible to find) source of funds proofs as a pretext, the fact is to seize and steal their users' funds is just a part of their business model.
By the way OP, I've added your case to the following list:
[INFO] Updated Summary of malpractices and abuses of exchangesPlease keep us informed of any developments.