OK,
You aren't getting any real help are you?
I believe the following is true: an iPhone 5c will support certain 4G/LTE "bands". A more recent iPhone (like an iPhone 8, or X) will support other "bands". A band is a range of frequencies that the carrier uses to exchange information between a tower and a phone. You can think of your phone as a specialized 2-way radio, and if branded a Verizon device, is set up to speak/understand the radiowaves coming from and going to the tower(s) in your area.
I also believe, VZW is re-allocating their bands on their towers, perhaps modifying the signal levels, and also the pointing of their antennas. Why? I believe they are re-configuring their network for the future, the changing of protocols, frequencies, essentially cellular technology.
Some people with older technology phones (with built-in radios) are probably experiencing a sudden loss of service at their home, depending on so many factors and things I honestly don't understand completely, I couldn't explain it today if I tried. Maybe next week. 
At this point, I'd recommend the following experiment if you want to stay with Verizon: identify a co-worker or a neighbor with Verizon as their carrier AND an pretty recent phone: iPhone8 or X, or if you'd be willing to switch from the Apple OS to Android, a Samsung Galaxy 8, Pixel XL, or an LG V30.
Have them over to the house. Have them inside or outside make a call, surf the web. If they can do that, it's probable your phone doesn't support the bands / tower / antenna setup for the tower your phone is trying to connect to at your home.
