Question: How to sew bra into my wedding dress? Sewing Machines Parts and Sales in Los Angeles

I’m an intermediate sewist, and I haven’t been able to find a good answer to this on Google.

I am plus size and busty. I have a corset-back wedding gown with an illusion (mesh) neckline, and I have a strapless Cacique bra where the cups fit great but the band wasn’t attached correctly (so I got it for $20 instead of $100). Because of the band issues, I can’t just wear it under the dress.

Should I just keep looking for a good strapless bra or can I easily add my band-less bra to a gown?

EDIT:
Photos

Here is the promotional album from the vendor so you can see the dress structure. This is me in the dress without a bra or slip because I was too excited when it arrived in the mail.

Promotional image of bra, actual bra. The reason I can’t just wear it as-is, is because they accidentally made it a 29-inch band instead of a 40-inch band.