For the fees to be taken out, your refund was sent by the IRS to Block or whatever preparer, then they took out your fees and deposited the rest to your account. The IRS had THEIR account info, not yours, so can’t very well deposit your rebate to your account when they don’t know what it is. So you’ll get a paper check in the mail.

Look in the FAQ section under stimulus info – it’s there, and quite clear.