HELP! I'm pulling what little hair I have left out!

I started out with a Slap King upright with Full Circle Pick-up and Fishman Platinum EQ, even though it had a big bass sound most of the time I heard no Real tone and I thought it lacked in the G string area. I broke the little weak wire on the Pick-up wheel so that pick up is done.

I just bought a Big twin and Golden Trinity combo with blender I was not impressed the first gig two weeks ago and I still am not. The unit came with a broken stereo cable and for the life of me I cannot get a good loud sound, I play Rockabilly, Big Band and a small low volume jazz gig, it’s either volume and no tone or tone and no volume the feedback is ridiculous. I moved far away from the speakers, turned off the Mic, stuffed cloth everywhere, tried the pick-up on just about every part of the bass. Is it just too much to ask for volume and tone? Did I buy the wrong pick up, am I doing something wrong?