Experience Proof: No PF Records, documents advice required?

Hey folks, I was part of this small startup where I started off earning 15,000 INR for the first five months. Later, my salary bumped up to 25,000 INR per month. The odd thing? My salary slip didn't have any deductions like PF or other perks. Fast forward a year, I decided to move on and resigned. Now, I'm scratching my head about how to prove my 1.6 years of experience to other potential employers without those typical deductions on my payslip. Can you help me figure out what kind of documents I should gather to showcase my experience effectively? Your suggestions would be a lifesaver!