Correct spelling of POISHA

Md. Abu Siddique, Paribagh, Dhaka
I spell POISHA as I have done here. Poisha is our smallest coin. It is one hundredth part of a Taka. Its plural is POISHA and abbreviation Ps. The Bangladesh Post Office issued stamps spelling POISHA correctly. PAISA is the smallest Pakistani coin and PAISA its Indian counterpart. So far I recollect, there was an ordinance or a President's order back in 1972 or 1973 defining our currency. Some people, even newspapers and banks spell POISHA as PAISA which is wrong. I humbly draw the attention of the Bangladesh Bank and The Bangladesh Post Office and request them to enlighten us on this topic.