You are having problems with getting emails that are being blocked by your ISP(iNet) anti-spam filter. Not sure why you think it’s the cart vendors issue. Thousands of transactions are processed by cartloom all the time without a problem.
Your problem appears to be with the ISP or the software vendors but not the shopping cart folks. If you have an issue with two stores in a shopping mall, do you blame the mall owner?
As for YourHead software purchase (plus kit) did you look at the footer on every page of there site there’s a link to finding a lost serial number along with links on how to get support.
As for one little design they have a support link right at the top bar navigation did you click that? There’s also a serial number lookup on that page and instructions on how to contact support:
https://onelittledesigner.cartloom.com/lookup
There’s really nothing cartloom can do to help you out much more than they have. They can’t get you your blocked emails, they don’t and shouldn’t have access to your purchase information including serial numbers from the individual vendors using their product.
If you follow the instructions from @yabdab above from your ISP and turn off the spam filter, then enter your email address on both sites serial look up they will resend you the emails. If that doesn’t work then contact their respective support areas.