A Chinese user of the cryptocurrency exchange ZB.com said that the exchange reported him to local police in a post on the 8btc forum, a major Chinese crypto community, on Jan. 21.

In the post, which has been viewed over 12,000 times with 135 comments, the user claims that ZB.com froze his account containing a 400,000 yuan ($58,000) balance. The user surnamed Zhang said that the exchange called police after he earned money on the ZB.com platform.

Zhang claimed that he tried to report the asset freeze to police, but was rebuffed when authorities said that no case could be filed, as he could not provide basic information like the exchange’s address.

The account was reportedly frozen after Zhang violated part of the user agreement stating that:

“Users shall not maliciously interfere with the normal operation of crypto asset transaction, and shall not influence the normal operation of the platform and other customers’ activities on the platform by any technical means or other means.”

Zhang reportedly realized that there are no pending orders with a bid ranging from 10–20 yuan ($1.47–$2.94) on the platform. Accordingly, if he posted buy orders offering over 10 yuan and posted sell orders higher than the buying price, buyers and sellers would always take his orders and he could keep the difference.

He reportedly made frequent transactions with the PCC/ZT trading pair, earning about 700,000 ZT in two days, worth about 200,000 yuan (equivalent to nearly $30,000). On the day before his account was frozen, he sold 10,000 PCC.

Earlier this month, ZB.com briefly overtook Binance and became the top cryptocurrency exchange on CoinMarketCap when it saw a daily trade volume of $606.7 million.

Recently a report revealed that, despite an increase in the decentralized cryptocurrency exchanges, their centralized counterparts still control over 99 percent of the total crypto exchange volume.