Microcell - calls cut in and out on my end with voicemail and 3-way/on-hold calls

I've done some searching through these forums as well as others and I'm not seeing anyone with the same problems I'm having.  Hopefully someone on here can help me out.

First some background.  I'll start with saying Samsung phones are terrible.  I had a Galaxy S4 and had an issue with the phone not ringing when people call while I was at home.  Changed to LG G4, problem was gone.  Upgraded again to the Samsung Galaxy S6 Active and problem comes back.  Doubt that it's coincidental.

Since I work from home I figured I'd try the Microcell.  For the most part, problem is fixed.  Everything connected ok, activated, phones connect to Microcell, phone now rings when people call all the time.  HOWEVER, there's another odd issue with call quality.  Here's the symptoms:

1. If I call someone and they answer, sometimes I can't hear them for a half a second.  Then everything seems to be ok.

2. If I call someone and get their voicemail, the sound cuts out on my end, goes on and off for about a second at a time.  I can't understand their end and so I almost can never leave a message.  I think this seems to only happen when I'm calling another cell phone and not on landlines.

3. If I'm on the phone and someone calls me, if I put the original person on hold to answer the other call the sound cuts out for a second, in for a second, out, in, etc.  I can't hold the conversation and I have to drop both calls and call them back.

4. If I'm on the phone and try to initiate a 3-way call, same problem.  Cuts in and out.  Doesn't matter if it's a cell or land line.  If someone else initiates the 3-way call everything works ok.

I'm on Charter internet with continuous 95+ Mbps download and 4+ Mbps upload.  I have quite a few devices on my network but I've not found anything stating that this would be an issue.

Anyone else have this same issue?  Any tips on what to try?  I've looked through Otter Pylot's guide but I'm not having connectivity issues, just these odd problems stated above.

Thanks in advance!!