I've spent all afternoon on the phone with Verizon about this, and nobody has been able to do anything.
I recently moved to downtown Chicago, and the service here is awful. Worst service I've ever experienced. I routinely get dropped calls (I can't hold a call for longer than 20 minutes max without it getting dropped), even when I stand right next to a window, with no obstructions/buildings/etc in the way.
I've called technical support twice, and they have been unable to help me. At the end, they said that the only solution to my problem would be purchasing a network extender. But they cost $250, and I'm not going to spend $250 just to be able to use the service I already pay for. (I know for a fact that at least Sprint will give you one for free if you have service issues, I imagine other wireless companies are probably similar.)
Is there really nothing Verizon can do? I've been a Verizon customer for several years, but since nobody seems able to do anything (I've spoken to about 10 different customer support and tech support reps and "supervisors"), I'll probably have to switch to a new carrier. Seriously, you'd think Verizon would be itching to help solve the problem to keep a happy customer, but nobody seems to care at all.
(Oh yeah - about an hour ago, my call to Verizon dropped, and now whenever I call back, it refuses to let me in - it says something like "Sorry, we're unable to connect your call at this time." What a lie...)
Being prepaid you are at an advantage. You can come and go as you wish. Verizon cannot do much to improve your service and an extended is not the answer. Your best option is to find a carrier who has coverage for your area.
The thing is, I'm not certain which carrier does have better coverage. By all reason, Verizon coverage should be excellent here. My apartment is fairly high up, there are no obstructions, I have giant windows, yet even when I stand next to them I get dropped calls. Unless Verizon's service is actually spectacularly terrible in downtown Chicago, I don't see what else could be causing it.
By the way, my phone apparently doesn't really work with other carriers - I'd need to purchase a new phone. I have an S4 and although it seems like I could bring it over to T-Mobile, I won't be able to get any 4G, which is unfortunate.
Try installing this app and see if you can figure out where the nearest tower is and where you're signal is at its best. It could be that the tower is on the other side of the building from you and being next to a window won't help. While it seems that things should work well among the buildings sometimes they cause more problems because the signals end up bouncing around which causes more problems. When looking at the app you want to focus on the 1xRTT signal not the LTE since that is what is used for calling. Not sure if the S4 supports Advanced Calling (HD Voice) but if you are showing a stronger LTE signal you try enabling it on your account if available for your phone.