At least you should call them first before port out. I also kena before. They still insist that port out at any date still have to bear full subscription charge.
Plus Celcom loves the lawyer. After 2 bulan tak bayar bil after MNP hantar surat lawyer. And the worst thing is they said will send final bill once MNP to other telco but the bill never arrive in my email or my mailbox. There is not even a call from them to pay.
They send a love letter from a lawyer claiming I have not paid the bill yet after that two months. Stupid Celcom.

Call them and pay via respective bank website you have. If not go to Center. Jangan surat lawyer sampai sudah.

Ok well done! Now can rest in peace. 😂