Capitol One 360 Taking back interest because of authorized transaction. Internet

Capitol One took back $.01 of the interest they paid me on checking account.  They claimed that because a $21.00 transaction was authorized but not paid until the 2nd of the month, that they paid me interest in error.   The transaction was authorized on the 30th of the month and paid on the 2nd.

First the money is mine until it leaves the account.  An authorization inquiry is just that an inquiry that funds are available.  But the funds are still mine until they are actually paid out.   So not paying interest on these amounts is simply another way of fleecing the customers of money.   I am currently checking if they disclose this sufficiently and completely.

Second the interest on $21.00 for two day at 0.75% annual interest they pay is $0.00045 per day.  So for three days this amounts to $0.00135.  Just over 1/10 of one cent.   And for that they want to charge me a full penny.   Sounds like a great way for a bank to make money. 

This also throws into play the honest and fairness of this company.   It sounds to me like Capitol One is slowly destroying the ING ethics of this company.