Unfair treatment

I bought an electric water pump for a BMW 320i msport A/T on the 25/08/2021 for R5500 and had to change it again this month as it gave in.I called D and H to ask them about the warranty to which they told me it was 7 days and they cannot do anything if the part breaks. Now my question to them was should I buy a water pump after every 4 to 5 months and they said it was not their problem