how do I get my tax return back?

Hello, everyone. I have a student loan that has been in default. I have agreed for wage garnishment. My tax return has been taken for two years and this will be the third year. The amount of my loan has not changed and im concerned that my return was not been put toward repayment of the loan. I am financially struggling and have kids to support. I haven't been able to get the earned income credit because it is taken with the return. I've called the ed. dept. and the debt. of treasury for answers but keep getting the run around. I haven't called the collection agency because I'm afraid of what the outcome will be.I have no problem making an effort to repay this loan but I feel it should be a lot less and need my tax return. how should I go about handling this issue