|Stuff comes up for 'icoustic' but not when paired with 'ramp04'. There does seem to be a 'tamp04' and a 'tamp06' mp3 player made by icoustic. Could one of those be the item?|
There is an icoustic.com but they seem to deal only in guitars. Does the manual you have give a website for the product?
I'm sure there's a battery inside but those batteries usually last for years and will probably outlive the mp3 player so it may be sealed in and the only way to remove it would be to destroy the player.
If all else fails I'm sure you can return it.