Where is Langfang PICC?

The best chance is to report the case in Langfang. PICC supports national requirements. You reported the case in Langfang, and PICC took photos at the scene. After taking photos, you can go back to Tianjin to repair your car and get compensation in Tianjin.

Now all you have to do is find a suitable place in Tianjin, bump it gently and call the police. Of course, you can't say Langfang. However, it is risky to do so, which may be discovered by experienced claim adjusters. For example, there is no scattered object near the hit object, and there is no car paint on the hit object.

Further reading: How to buy insurance, which is good, and teach you how to avoid these "pits" of insurance.