15 (or so, hard to count

) flashes indicates a dead battery. Subsequent button presses without charging will give the same result.
Green light on the charger without the Spinner light being on indicates a bad connection to the charger. Unplug the charger from the wall wart (or usb port), take the battery off and clean both contacts. A swab dipped in rubbing alcohol works well, or a twist of tissue dipped in same. Allow ample time to dry. Then try charging again. The charger should go red, the battery light will go on for a large part of the charge cycle. Once the battery light goes off, leave it ON the charger until the charger light goes green for a full charge.
If that doesn't do it, you may have attached your topper too tightly and pushed the contact pin of the battery in a tad. Doesn't take much to lose the connection. Easy fix. Many of us have done the damage and the fix.
Turn the battery OFF. (5 fast clicks.) Using a jewelers screwdriver, eye end of a large sewing needle (careful, the other end is sharp

), straightened out paper clip, put it down into the top of the battery next to the post and lever up gently. Go about 1/4 of the way around and repeat. Go all around that way, gently. You probably only need 1 mm or less of upward movement.
Turn it back on and try again.
Good luck!