Voles are destructive, but I wonder if you have a groundhog going on.

I think you probably have both. If they sucked your pepper plant straight down through the ground, then probably voles are the culprit. But voles can not be that destructive, completely eaten you squash, beans, carrots, cucumber!? Sounds like groundhog to me, only groundhog can be that destructive! Try using a big trap to get that groundhog trapped, and don't give up gardening for this year yet. You can still grow lots of thing especially in the fall garden when the groundhog's tend not to be so devastating, even if you don't catch them.

Trap him. I recently trapped a pocket gopher tunneling under my plot. I did alot of research ahead of time and trapped him within 24 hours. Ground hogs are bigger I know, but it can still be done.

If you have gophers in your area you'll have to go with the hardware cloth, raised beds rout.
People are going to pooh pooh me, but I've had a lot of luck with a thingy that you put down in the ground that is run by C batteries. It "chatters" every 30 seconds or so.
The only gopher activity we've seen in the last 3 years since we started using it is when the batteries went dead when we didn't realize it!
We got our first one at a Big Box store for about $25. We have since found several at thrift stores and plan to place them in other areas of the property!

I have had terrible vole problems in the front garden for the past year and a half. I have an outdoor cat and she takes care of the voles every where else, but the front garden bed is close to the sidewalk and I don't like her going near the road. The voles were out of control up there and they were progressively wiping out my perennials!

I tried a vole trap without success - perhaps I didn't set it effectively. But I successfully protected the plants from the voles in 2 ways - 1) using hardware cloth cages that circle the root systems of certain plants they love, and 2) using a mixture recommended on the Hosta forum - I put a big spoonful of castor oil and about a pint of urine into a big watering can of water, and sprinkled the plants. Could not believe it, but it really worked! I actually got to see 2 of my native wild Hyacinth bloom thanks to the castor oil. (apparently, it makes the roots taste really bad??)

If it's woodchucks, then I use wire fencing to encircle the plants they like (kale, cruciferous veggies, etc).

I found some wire trashbaskets at the dollar store and plan to use them for individual enclosures for potatoes. I've tried all the silly remedies -- sticking gummy bears or gum in the vole runs, stomping the heck out of them, destroying burrows, etc. The cats catch a lot of them, but there are always more. I pulled my parsnips yesterday rather than having the voles eat them.

The voles never touch tomato family crops or beans, and in fact when the spring root crops are gone they kind of disappear, probably gone to eat the Jerusalem artichokes on the hillside. I see very little of them in late summer.