Recieved a message from Hollard with TFG details to say my policy will be terminated but TFG or Hollard cant assist

I recieved a letter on a Hollard Letter head saying that my policy will get terminated tonight, with no reason why, and the letter has TFG contact details on it, when I call that no on TFG they tell me they dont pick up anything on their system for me, yet it is a Hollard letter with TFg contact details and TFG cannot assist me, then I call Hollard and they cannot assist me. So who do I call now to asssit, because now it will be terminated- my id no is ***