How do you write a letter to bank manager for unblocking my ATM Pin Code?

Dear Sir

I have a SBI ATM card. I had lost the card so I requested to block the card.

Now I have found the ATM card and I have requested to Unblock the card now, It has not being unblocked yet.

I have given written request twice to the Branch Asst Manager, and also have sent e mail several times to the head office in Banglore as well as in Lucknow.

still the card hasnot being unblocked...