Hi sir/madam, you don't worry, you have to issued a legal notice to the said employer for wiling to serve notice period and to return the original certificates at the time of relieving the job. If the company has failed to give opportunity to serve the notice period and to failed to give the certificates and stick the compensation in lieu of notice period, at that time you have to file petition before jurisdictional district labour commissioner in this regard, they will settled the matter by giving relief which you want. You go ahead in this way. They cannot fit to you in the black list and terminate you without proper reason. If you want my legal service in this regard I will do it.