Hi shoanrebero,
First, try talking calmly to your employer and ask them NOT to renew your employment visa. Tell them that you would want to be relieved from your job.
Since no employer can hold back an employee who does not want to continue (since that would amount to unlawful practices and human rights violations), your employer should let go of you. Since there are no proper exit procedures agreed prior, the employer could make the most of the situation.
If your employer refuses to send you back, you have every right to take up this serious issue legally - with the Oman Ministry of Manpower, as well as the Indian Embassy in Muscat.
Once escalated, the authorities would step in as mediators and would settle the issue amicably.