I'm not a tax professional, but I can provide some general guidance on how you might approach your situation. It's important to consult with a tax advisor or attorney to get specific advice tailored to your circumstances.

1. Attempt to Communicate: Before taking any further steps, make one last effort to contact your partner and inform them about your concerns. Document your attempts to reach out, including dates, times, and methods of communication.

2. Review Partnership Agreement: Examine the partnership agreement or any other legal documents that outline the terms and conditions of your partnership. Look for provisions related to dissolution, withdrawal, or termination of the partnership. These documents may provide guidance on how to proceed.

3. Consult a Tax Advisor: Engage a tax advisor who specializes in partnership tax matters. They can help you understand the potential consequences of your partner's actions and guide you on the best course of action.

4. File Amended Tax Returns: Since you haven't received a K1 from the partnership, you should consider filing amended tax returns for the years in question. Include any income or losses from the partnership that should have been reported. A tax advisor can assist you in preparing these amended returns accurately.

5. Seek Legal Advice: If your partner remains unresponsive, you may need to consult an attorney to explore your legal options. They can advise you on potential remedies, such as dissolving the partnership, pursuing legal action, or negotiating a buyout.

6. Document Everything: Throughout this process, maintain detailed records of all your efforts to communicate with your partner, your financial contributions, and any other relevant information. These records will be valuable if you need to take legal action or resolve any disputes.

Remember, this information is not a substitute for professional advice. Reach out to a tax advisor or attorney who can provide guidance based on your specific situation and applicable laws.