visible doesn't just use Verizon, it IS Verizon, they(Verizon) own it(visible). it's their discount carrier..similar to At&t and Cricket...
are the signal issues just at your house?
because a booster/repeater in basic terms is a box that (usually) connects to your internet connection,(and I clearly could be wrong on that) and puts out their phone signal in the immediate area. it's not super powerful of a broadcaster (in line with wifi, or cordless phones) so don't expect it to fix a large area...
what you can check into is if your phone is capable of wifi calling. if so, turn it on, and make sure the phone is connected to your wifi network.
it(wifi Calling) was a blessing on my last trip to Canada... I'm on Verizon Prepaid, and they had JUST added travel pass to the prepaid system. I had everything set up from my end, new phone, travel pas activated on my account, extra funds loaded into my account (cost $5/day) but as soon as i was out of range of US towers, I had no signal. but i was able to use the wifi at their travel centers and at my destination to make calls/etc.