Let's be fair

I bought a lawnmower which came with a trimmer last year October or so at Builders Raslouw. The trimmer stopped working in December and i went to the store but the person that assisted me told me that i need to bring a receipt which is not in my possession or a bank statement. The thing is im not sure which are did i use to purchase the material and during that time i spent more that R30 000 because i was also painting my house. My thing is that the trimmer has a serial would you not be able to see when it was bought and honestly i dont have the time to do the admin with the banks to get the statements. Does this mean i must buy a new trimmer because you are unable to assist me.