I had to letmy Apartment go about 7 years ago.I lost my Job. I have been paying 110.00 to 15.00 per month 0n a debt that they said I owe. I am unemployed in school and living off my financial aide. My father co-signed and he receives social security and a pension. I got aletter today stating that the cannot excecpt my 15.00 anymore the want $50.00 dollars a month. Can they garnish my Fathers Social Security,Pension or checking account.

They can of course accept 15, but it is possible that the interest each month is higher.
They can not garnish anything, until they go to court and get a judgement. Unless they have already done that.

Have you been to court, or were notified of court?

If your father co-signed your debt, then he is on the hook for the debt. They can't touch his SS, but they can attach his checking account, if they get a judgment and a writ of execution.