To get test funds in sandbox, use the simulate transfer in the Anchor Dashboard.
You can simulate incoming payment to get test funds in sandbox mode. Below are the specific steps to fund an account in sandbox
In the Anchor Dashboard sandbox environment, go to the Accounts page, select Deposit Accounts then click on the Simulate Transfer button.
Fill the form by filling out your API Keys, Source Account Name and Source Account Number, and select the Virtual Account Number (Virtual Nuban) you want to fund. (Note that the Source Account Name and Source Account Number can be random values).
The fund will reflect in the deposit account linked to the Virtual Nuban.