iPhone 6plus 64GB having incoming call/voice- and e-mail problems

my iphone 6plus is acting up. Normally I like to do any of my iOS updates while I am tethered to my MacBookPro using iTunes. That way I can do a backup that is store on my laptop.

Lately, I have noticed that Apple keeps sneaking in iOS updates (11.2.6) that somehow get downloaded - then they ask me if I want to install them later. It ****** me off that Apple can force my phone to download a large amount of data and all I can do is mess around in the settings to delete it - but it keeps coming back. This has only started happening to me in the last couple of weeks.

I should also mention that I had contacted Apple support a few weeks ago and asked them about battery replacement for the phone. The Apple Support tech asked me if I could allow her to remotely access my phone to see the battery recharge cycles - so I allowed her to do that. I assumed that once I disconnected from the call, that was over and done with. I never had the phone start downloading iOS updated BEFORE I contacted Apple Support about the battery issue and did the remote access.

I was out of town the last couple of days, and the damned update (11.2.6) somehow got downloaded AGAIN - but maybe also was corrupted somehow. So I installed the update while I was out of town away from my laptop. The iOS I had on there before was 11.2.5.

Lo and behold, I started having some real problems receiving e-mails on the iPhone built-in e-mail app, as well as receiving phone calls and accessing my voice mail messages. I was seeing e-mail headers but was unable to see the body of the e-mail - it just wouldn't show up/download. The same goes for my voice mail messages - I was even seeing an wanting to play a specific VM message, but the phone wouldn't play the one I wanted to listen to - it would play one either above or below it. And then when I want to delete the voice mail, it fails to delete - it just pops back up.

I should also mention that I was having problems with certain apps (Firefox and Safari) opening up certain pages and sites and freezing up - like it wouldn't allow me to start entering text messages in FB messenger

I have someone trying to reach me late Friday (I finally got a message after 5) about work who insists that they sent me several e-mails, called me and left voice mail messages several times, but I couldn't find those calls or e-mails.

I got home over the weekend and back on my laptop, and there were the e-mails - sent to a G-mail address that I used to be able to access 100% of the time on my phone. A friend suggested that I backup my phone and try to do a full restore while the phone was tethered to my laptop. I did that - and now I can see the missed calls and the voice mails, but not the e-mails.

Has anyone had this happen to them with the latest iOS update?