A petition against GTBank just saw it in my mail box from change.org, the content of the petition is added below

On February 26 and 27, Nigerians were able to use their GTBank Naira cards to withdraw money and make transactions in dollars at the exchange rate of N199 (one hundred and ninety nine Naira) to the dollar. This was a welcome development, to be able to transact at the market rate instead of the near Black Market (parallel market) rate of about N300 (three hundred Naira) that the Bank had been charging its customers for weeks. So, GTBank customers used their cards for transactions that they probably would not have ordinarily made, encouraged by the slashed rate. However, on February 29, the Bank communicated that it had experienced a "system anomaly" and would "automatically correct all transactions that occurred between ...[the relevant] period and apply the correct or applicable exchange rate at the time of initiation". It then proceeded to debit the accounts of customers who had used their cards and relied on that rate during that period.
Without going into the legal implications of such a transaction, we can consider the ethical implications of a Bank that allows customers to change their positions, many significantly, relying on the "the settlement amount ... advised" by the Bank, only to have their conditions fundamentally changed based on a "system anomaly" of the Bank. In layman's terms, customers are being punished for the Bank's mistake/incompetence/systems error (??), having relied on the Bank's communications and systems.
For months, customers of GTBank have paid more than 50% above the market rate for transactions made in dollars. The explanation is that "The exchange rate applied to International Card transactions is a reflection of the trend in the economy." However, it is not clear how this most recent act of the Bank is a result of the trend in the economy.
Nigerians have been resilient enough as the economy trends in ways that many of us can hardly understand, but we expect our government and its regulatory agencies to protect us from the acquisitiveness of individuals and institutions that seek to exploit innocent citizens and unsuspecting customers, relying on the current economic condition as the basis for their actions.
THEREFORE, WE CALL UPON THE CENTRAL BANK OF NIGERIA TO STOP GTBANK FROM EFFECTING THIS "CORRECTION" AND TO REPRIMAND THE BANK FOR EVEN CONSIDERING SUCH AN UNETHICAL MOVE.
WE CALL UPON THE NIGERIA DEPOSIT INSURANCE CORPORATION TO PROTECT THE INTERESTS OF BANK CUSTOMERS WHO DEPOSIT THEIR MONEY WITH BANKS TRUSTING THAT THEY WILL NOT BE EXPLOITED TO MAKE UP FOR THE BANKS' ERRORS
WE CALL UPON GTBANK TO REVERSE ANY FUNDS THAT HAVE BEEN REMOVED FROM CUSTOMERS' ACCOUNTS, TO ISSUE A PUBLIC APOLOGY TO ALL ITS CUSTOMERS AND TO ASSURE ITS CUSTOMERS AND THE PUBLIC THAT IT WILL NOT REPEAT SUCH AN UNETHICAL PRACTICE IN THE FUTURE.

The link to the petition
https://www.change.org/p/central-bank-of-nigeria-stop-gtbank-from-profiting-from-making-customers-pay-for-its-incompetence-and-greed