I spent 9.9 yuan to buy an APP on the whole network. After downloading according to the operation, I always feel too cheap and unreliable. What should I do? Has anyone used this software?

This should only be installed, and you may be asked to buy a member or charge some viewing fees in the future. It is normal to buy an installation software cheaply, but many softwares are used at a later stage for a fee. Security is ok in many cases, because you are just an ordinary person and don't involve so many secrets.