You mentioned that you were having trouble holding the new wig on. OK, here's how you do it. Go to a craft store like Ben Franklin and buy a 2' by 3' folded up sheet of brown or gray plastic foam. It's about a sixteenth of an inch thick. It is easy to tear off, but don't do that yet. Cut the foam with scissors into 1.5" strips long enough to encircle your head where the edge of the wig rests on your head. You'll probably have several inches of overlap. Stretch the strip about 2 inches longer than it lies by itself, then tear off what is in excess of a four or five inch overlap as it goes clear around your head.
Put the foam over your forehead at the level where the bottom of your wig cap will come. Put it just above your ears, like the wig will go, and down in the back to the level of the wig cap in the back. Then take four BLACK bobby pins, open them and slide them in with the short, spread-end side next to your scalp (scooping up your hair), and the long side on the outside of the strip. Put the first pin on one side of the back of your head at the end of the overlap. Then put in the second pin, criss-crossing it over the first, so that one is holding the other even more tightly shut.
Put the second two bobby pins on the other end of the overlap in the back, being sure to anchor them under the foam in your hair, because it's your hair that's going to help hold the wig down.
Take a rat-tailed comb or brush and slide it up under the hair of your sideburns and above your ears until the hair is lifted and secured under the plastic strip.
Put on the wig.
Take two of the long, oversized black bobby pins. Secure the front of the wig to the plastic on your forehead by sliding one side under the plastic and the other just on top of the wig cap but under the wig hair. Then comb the bangs or front of the wig forward enough to cover the ends of the bobby-pins. (Relax, the front bobby pins don't have to be anchored to your own hair in the front; if your hair is like mine, they don't make bobby pins long enough to reach the real hair line.) Margie King (My wig merchant) swears that once you mount your wig this way, it'll never blow off, even in a high wind. Within my experience that has been true, although a windblown wig can surely be a mess.
Now you may have one more problem. If you have sideburns in front of your ears, your wig may not cover them well. I cured part of that problem by chopping mine off at the level where my glasses bow passes over my ear. But some wigs will still tend to blow or work back so that darker or different colored hair shows there. Here's how you fix that.
Get two BLACK (even if you have light brown hair) regular old hair pins. Take one side of a pin in your hand and bend it double right in the middle, so that the end of the bent piece is now back next to the first bend, with all three parts of the pin now parallel. One piece is still sticking straight out as it was in the first place. Slide that long piece under the plastic strip in front of your ear right where your hair might otherwise show. Be sure the rest of the pin sits on the outside of the wig cap, but beneath the wig hair. Bring some of the wig hair forward, and slide it into the 'hook' you have made with the side you bent. This will hold the hair forward so that it can't blow back away from the side of your head there. Then brush some hair over the top of the pin so that none of the pin shows.
You now have a well-anchored wig that you can wear all day, probably without any slippage up the back. You can reuse the plastic strip several times before it stretches too much or gets too many holes in it from misguided bobby pins.
If your hair is so thin in the back that even this doesn't keep the wig from working up during the day, there is still one more thing you can do. I've tried it and it works. Surgical supply houses sell little bottles (2 oz) of roll-on, water soluble adhesive for holding on bandages and holding up women's stockings. It is not only perfect for making sure your thigh-high stockings never slip down at the top, but it can be used to hold the plastic strip stuck to your head in the back where you are pinning it. Just roll a little across the back of your head, overlap and pin the strip, and it won't move until you tell it to.
The adhesive will wash off when you shower or wash your hair--or even with a wash cloth--it's not a tight stickem. And it will wash out of any clothes or stocking you get it on. Neat stuff. The brand I have is called, "IT STAYS" Roll On Body Adhesive.