Employer not letting to quit after the expiry of the contract

I'm working in one of India's reputed company as a consultant on yeraly contractual basis. On 31st of August my contract got terminated. And I have been asking for new contract since 1st of August and nobody replied. On 1st sep HR mail me and ask me to continue my service and told me theat they will provide it soon. Then on 14 th sep they gave new contract for another year. And after evaluating the contract I decided to quit. But to raise the salary for the period after termination of contract and and till the date work done i.e 1st sep to 14 sep I will have to sign the new contract and then I shall quit by give one month advance notice as told by my HR which is total harassment. so how should I deal with it ??