Question Summary:
Is it sinful for me to keep the money loaned to me by the banks due to money taken from me by the state?

Question Detail:

I was in U.K for about 3 years, I struggled to strive there as a student and didn't get enough working hours to save money which was my main motto to go there. I paid different taxes as a student and as a renter which is called as council tax, though I wasn't supposed to pay as I was on a student status but still I was forced to pay (unfair).
If I used to earn 100 I used to pay 15-20 percent of that as a tax which is supposed to be returned back to me when I leave the country, I didn't apply for that tax return coz I knew that I won't get it as they denied to other students, they would deny it for some xyz reason (u were a student and worked more hours etc).
My college shut down and I lost the fee I paid to them, I applied for a security license for getting a better and good job but I only got it after one year of delay from them and when I got it I had no valid visa as I applied for an extension and again I got this visa renewed after one year and I had to spend lots on this and there were many occasions to mention here but to be precise I have added the above situations. Finally I decided to quit and come India forever for good.
But I took out some good money from banks and credit card lenders and now I am in India and got no intention of returning it to them since they have looted me in different ways I feel I have done the same and anyway I haven't looted a person, I actually looted from their economic society. I have also thought about giving some money in charity and so. My question is have I done it right or wrong?
Is it a big gunaah I’ve committed or okay as I have just taken my money which I lost in taxes and unfortunate events? I agree that I have taken a bit extra than what I lost there, but I also plan to spend some money on the needy people. Please advice. JazakAllah.

Answer :

In the Name of Allah, the Most Gracious, the Most Merciful. 
As-salāmu ‘alaykum wa-rahmatullāhi wa-barakātuh.
We understand from the information you provided that you feel you have been treated unjustly by the state.  However, this does not justify one to usurp funds belonging to others.[1]  Identify a legal procedure to reclaim any money lost unjustly. 
Ask Allah for forgiveness and haste in repaying the outstanding balance on the credit cards.  One must be very cautious in matters relating to debt.  If we owe anyone any material right, money, property, etc. we should fulfill it in this world or else we will have to pay for it very dearly in the Hereafter.  Consider the following mentioned in famous Hanafī work 'Al-Ashbāhu Wan-Nadhā’ir':
"The reward of seven hundred Salāh with Jamā'ah (in congregation) will be exchanged (on the Day of Judgement) in lieu of (unjustly taking away another person's) one Dāniq."[2]
A Dāniq is a silver coin equivalent to approximately half a gram of silver.  This is a severe warning to debtors.  Can any one of us guarantee having at least one accepted Salāh, leave aside seven hundred accepted Salāh?
Therefore, you must pay back the banks and lenders.  It is not permissible for you to keep the money and not pay them back.
And Allah Ta’āla Knows Best
Mawlana Faraz ibn Adam,
Student Darul Iftaa
Leicester, United Kingdom
Checked and Approved by,
Mufti Ebrahim Desai.
www.daruliftaa.net