No. Tinderizer is fine. Amazon provides an email id for your device. If you send any document to that email address, then it gets delivered to your kindle. If you use Convert as subject line, then it converts the attachment into Kindle format (AZW3). Otherwise it will send the attachment as is to your device. Tinderizer uses this feature. To send email to this kindle device address, you have to whitelist the from address. It is one of the step that you have to do while setting up Tinderizer bookmarklet.

Account closure was due to different reason. Few months back I ordered a phone from Amazon India, but they delivered a perfume. When complained to CS, they closed my account with a vague reason reason that I violated ToS by using a duplicate account. This account closure after I had this account for more than 10 years and have used it in Amazon.com and Amazon.in. Earlier this month, I have a filed a consumer court case (similar to small claims in US) in India.

More likely they couldn't continue to use the service BECAUSE Amazon closed their account, therefore deactivating their kindle email address.