it says purchase code already used?

I don’t understand any of this. I bought this theme for a client who decided he didn’t like it because it ran too slow and I tried to upload it to my ftp for my website. It says it hasn’t been activated so when I put the purchase code in it says it’s already been used. I feel like I just wasted my money. I have had none stop problems. So are you telling me the moment I purchase it I can only use it once and I will lose it? I have never been able to properly use the theme.

You can only use it on one website.

So if you now want to use it on your own site then first need to entirely remove and deregister it from the client website

It was deleted from his website. Is there anyone I can talk to about getting my money back? I have never been able to use this website.

Refunds would only be applicable if the theme is actually broken Can I Get A Refund? – Envato Market Help Center

Your best option is to speak to the author How to contact an author – Envato Market Help Center, who should be able to deregister the theme for you (remember to share the purchase code Where Is My Purchase Code? – Envato Market Help Center) so that you can install it elsewhere.

Hard f…in work this. There’s no direct email nowadays. Basically, you pay for something and if it goes wrong ahhh well, your loss.

There’s nothing wrong - it’s very clear that themes can only be used once per license. All you need to do is speak to the author and it should easy to use again.

You can request a refund using the link on the refund info above, or contact envato Envato Market Help and Support but as per above, there has to be something broken, rather than a change of mind, lack of experience, etc.