All perfect praise be to Allah, The Lord of the Worlds. I testify that there is none worthy of worship except Allah and that Muhammad is His slave and Messenger.
You have to obey your parents when they request you not to use the mentioned application. We have repeatedly stated in previous Fataawa that it is an obligation to obey parents so long as they do not request one to commit a disobedience to Allah. It is an obligation to obey parents even in the permissible matters. As a matter of fact, some scholars are of the view that their obedience is obligatory even in matters that are considered disliked or doubtful. This is all due to their great right, as stated by An-Nawawi in his explanation of Saheeh Muslim and other scholars.
Therefore, you must fear Allah and obey your parents, because you would incur a sin if you do not follow their order, especially as they have a clear legitimate reason for telling you not to use it.
Allah Knows best.