New Discovery Miles inconsistent

I sent Discovery Card an email on the 26th of September 2019 asking about my Discovery Miles after I was migrated to Discovery Bank as I was unable to access them.

Discovery Bank sent a reply today (05/10/2019) saying that the miles would be reflected. So I go into my Discovery Bank app and from the time I migrated until now, I have only accumulated 400 miles. Previously, I would get 400 in a few weeks with the fuel spend.

There are also inconsistencies, spending R500 on fuel in August got me 10 miles and spending on R500 on fuel in September got me 5 miles. How is this possible?

Is there new rules with regards to Discovery Bank miles? If so, where is the document?

According to my calculations, the amount of things I used my Discovery Card for should amount to 1700 miles (WITHOUT the multiplier). If the same rules don't apply to both the Discovery Bank Miles and the old Discovery Card miles? Why am I using my card to buy fuel?