Philips Sonicare failed within 24-month warranty, proof of purchase unavailable

I bought a Philips Sonicare toothbrush for about R1 500 at Dis-Chem, together with two lower-priced Oral-B brushes for my children. About 18 months later the Philips brush stopped working. It was one of the more expensive brushes on the shelf and was used normally at home. I contacted Philips and was told a till slip is required before they will look at a replacement. I no longer have that slip. Dis-Chem has since changed systems and says it cannot retrieve a transaction that far back, so neither of us can produce the original docket. Philips lists a 24-month warranty on Sonicare toothbrushes. This unit failed inside that period. I am asking Philips to assess the brush on the serial number or date code, and to repair or replace it. I am disappointed that an expensive brush has failed this early and that the claim is stuck only because a till slip from a year and a half ago cannot be reprinted. I would like this resolved with a replacement or repair under warranty.

Model number: Sonicare G2, *** Failure: Not vibrating any more, motor dead