Mr Nath
Point wise I try to answer your queries:
(1) You will have to submit all the returns , but you will have to pay now heavy penalty for this. If you have provided taxable services during this period and total value was more than the threshold limit no doubt You will have to pay service tax even though you have not collected service tax. If you have not provided any taxable services during this period or your value of services were with in the provision of threshold(as defined), you can argue that you were not required to file return. In this connection refer to circular no. Circular No. 97 / 8 /2007 dated: 23rd August, 2007issued vide file no. F. No. 137/85/2007-CX.4.The provision related to your query, I reproduce herebelow:
6.1 The service tax return is required to be filed under Section 70 of the Act read with rule 7 of the Rules, by 'any person liable to pay the service tax'. This return is required to be filed on a half yearly basis, in Form ST-3. For the periods from April to September and October to March, it must be filed by the 25th October and the 25th April respectively. Further, ‘Input Service Distributor’ is also required to file this return. Persons who are not liable to pay service tax (because of an exemption including turnover based exemption), are not required to file ST-3 return.
On the basis of above You can argue that you were not required to file return.
(2) Yes you can take credit of the ST paid as said in your query, but for this you will have to pay service tax on the services provided by you and you will have to submit regular returns also.
(3) No this is not refundable, it is refundable in case used in export, refer to rule 5 of cenvat credit rules.
Thanks