Long pending s.t return

Sir,

We are proprietorship company and having service tax registration since 2005 with ( not pan no. based reg. no.) and on 29.03.2005 we deposit S.T through TR--6, but since than we have not submitted any returns.

Now my question is

1. Can we regularise the return? If yes, Please inform me how?

 2.Are we eligible to take the benifit of S.T credit of  S.T paid on Import of Material, On clearing and handling charges, On transport or courier charges, On Telephone and electricity bill?

3. Is the credit of S.T refundable ?

Please answer these questions to help me out.

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