Brave rewards lost after opening browser

I recently installed Brave on my desktop computer. When I opened it today it showed a rewards balance of 1.11 BAT. A few minutes later it showed 0.89

Why would the balance decrease?
Also today, the new tab page won’t load with an ad background no matter how many times it is refreshed or I open a new tab

Here are the details, one of the suport member asked me to restore my lost BAT token about 17 number, please help me to get back my lost bats

Wallet Id : aaa38a6d-9fe3-4773-a246-1718ed79abc1

Brave 1.20.103 Chromium: 88.0.4324.152 (Official Build) (32-bit)
Revision 6579930fc53b4dc589c042bec9d0a3778326974d-refs/branch-heads/4324@{#2106}
OS Android 9; vivo 1902 Build/PPR1.180610.011