At the moment, Mizar only supports BUSD on the Binance Smart Chain (BSC).
If you bought credits with other stablecoins such as USDT, these will not be credited to your Mizar account.
Mizar is not liable for any wrong transaction, make sure to buy Mizar credits with BUSD on the BSC ONLY.
Open a ticket here if you wrongly bought credits with non-supported stablecoins on Mizar.