My father said he did a sip on mutual fund during 1980s but don’t have that record how to claim it?

So I had a talk with my father today he said during his youth( 80s-90s) during this period he and his brother did a sip on stock and all he remembered was the logo and first letter and the location of the company. So I found out the fiance service company and it seems like a mutual fund but the thing is he paid month 350rs which the agent use to collect and give him a slip. So I asked him the slip he said it's not there as there was a flood in mumbai during 2004, If I remember. So there are no slips of payment. So I asked him whether he gave his pan card while creating a account for mutual fund ( like we have demat account to trade now). He said during that time there was no pan card. Now how can I claim those sip. 350rs monthly for a time period of 3-5 years that to during 80s-90s while be a jackpot now. Please help!