I guess Bitcoin is supported by Mudfish via BitPay API. Are you meaning that you're getting a error from BitPay while you try to pay?

the buying page submits to https://confirmo.net/landing with incorrect amount of LTC, while BTC is expected.

Please check http://mudfish.net/admin/credits/buy link. I think https://confirmo.net/landing link is dead now so you should not use it.