Repeater fields activation

I purchased the repeater field about a year and a half ago and I was told that it was a one time purchase. Now because of the different methodology of installing it it seems I need to purchase it again. On the website the only way to download it is to purchase it. I have an activation number but no where to use it. I’m pretty miffed because A. I either have to purchase it again and my client won’t be happy or B. It is unclear how I can activate/instal it within WordPress. Am I missing something?

https://www.ads-software.com/plugins/advanced-custom-fields/