You are most likely clipping the amp, causing fuses to blow. Try turning down the Gain on your amp and lower your Bass settings on your Head Unit before looking into buying a new amplifier.
Also, if you want to upgrade your fuse, I would only increase the fuse rating by 5 (example: Upgrade stock fuse 30 to 35). Any higher and you may end up damaging something.
If problems continue to occur, then I would suggest calling the manufacturer's tech support line about the problem, and see if they know anything about it and how to fix the problem.
If they are unable to help, then I would sell your current amp on Ebay and look into a more reliable amplifier.
