i paid quite a lot of money (accidentally purchasing it twice but then changing it to two years instead of one)
i emailed them a few weeks ago about getting my activation code again since my computer needed a reboot and i had lost it, no response.
Who did you email, ie. what email address did you send it to?
Did you use your same email address that you used when you purchased CCleaner?
Have you checked your email spam folder? Sometimes replies can end up in there.
Have you tried the licence lookup tool? Use the same email address that you used to purchase.
https://www.ccleaner.com/support/license-lookup
Note that the lookup tool is currently working for some but not for everyone, they are working on fixing it.