At this point, not only did yoi gave them money but you are also giving them your data for free which they can sell in the future.
The OP did not mention if he had deposit the money at the exchange. When you upload the data (KYC), on the site, they can still sell your documents to anyone without knowing you and without banning your account. There is no need to ban your account in order to misuse your account.
That is the reason that we should only do KYC at the trusted site, otherwise our privacy, our data can be misused and in some cases, we never know where our data is being used for unlawful purposes.