I'm having three years of total experience and have worked for two companies; my current company is the second one. I've received another offer now, but the issue is I've misplaced the offer letter and relieving letter from my first job. How can I convince the current employer (new job HR) regarding the papers from my first job? I've already approached my first company's HR, but they are not responding. I have one and a half years of experience in that company. What should I do? How can I convince the new employer?