Something is wrong with my tank help plz?

[ementa1]

Well heres the deal. my friend bought a dxs 48/45 off ebay from one of those ebay stores and well he quit before he even got to use the tank.(this was like 4-5 months ago)

So now that i have it i took it out to the field the other day and noticed that i would lose pressure when im rippin. Single shots are fine but when i got to about the 4th or 5th ball i lose pressure drastically. and after i stop shooting i hear a hissing sound like my tank is powering up again. any ideas on what it is and how i can fix it?

[ementa1]

and when i shake the tank theres something loose inside

[ementa1]

up

[tecdady]

send it to the manufacturer. nobody around here will work on it due to liability issues. the reg is having recharge issues. bad reg.

[ementa1]

is there a way for me to just buy a reg and fix it in a jiffy. or is it just way too complicated?

[ementa1]

And if i have to send it to the manufacturer how would i do that because i dont have the address or anything plus draxxus doesn't even have a site.