Is this debt collection or is it true?

It should be fake. If you are a regular policeman, there should be a formal and official process, not just sending a short message, which may be more serious, in order to shock your mind. If the other party is not sure whether you will pay back the money, you can discuss using WeChat applet to say online electronic IOUs to assure the other party that you will pay back the money within the prescribed time limit. In this way, the reputation will not be affected, and the other party will rest assured that it will not frequently collect debts and disturb your life.