My sub-account no longer exists. Why do my imported forms show up to that sub-account instead of the main account?

I guess your main account is lmuccin2, I did not find any "sub-account user" in it. could you share the forms that are not longer shown in your main account?

Simply get the direct link:

I guess those forms are actually hosted in another account,  meaning these forms were shared to your main account. If you want to, we can transfer the forms over the main account.