How do I … i have received notice for short payment of tax, but there computation is wrong, what do i do ?

in my return i had taken x amount of short term capital gain, which they have seemingly taken up at full rate tax, thus giving short tax notice
When i have checked i found that i have undercalculated my regular income tax by 10k and for short term capital, taken wrong amount and thus paid excess tax, net net i need to pay only 5k plus interest extra, what procedure do i use to sort this?

How to recover money remitted to wrong act now?

A friend of mine has sent some money to a wrong act. Money was debited from act of State Bank of Patiala to SBI. Later he came to know that it was not the act he had to send the money to and problem is that the act to which money is transferred, exists. Now, how he can recover that money? Please help.