Most of the complaints I've read have been due to the RALs being denied by HSBC. This is mostly due to a person having an IRS 'Refund Offset'. This is caused by such things as owing back taxes, owing outstanding student loans, or other government guaranteed loans, or owing back child support.
Neither H&R Block nor HSBC has any way of knowing if this applies to someone until after the return has been filed. Unfortunately, since the return has been prepared, filed and accepted by the IRS, H&R Block CANNOT get it back for you to go home and do it yourself.
However, the possiblity that this could happen and the reasons for it are spelled out in the multiple page loan application. The tax preparer is NOT going to read this whole thing to you, so if you can't read, then get someone to read it to you. It specifies that if your loan is denied it turns into a RAC, your loan interest fees will not apply and your refund will be released to you as soon as HSBC gets it (8 - 15 days) for whatever amount is sent by the IRS less your other fees.
If you don't think the fees for the RAC are acceptable for you, then I suggest you don't apply for the RAL and do your return yourself and get the IRS to direct deposit the money directly into your checking account in the first place.