Notification node isn't deleting notification and its data on ImageView click when it should be

I've got two methods in my Activity, one to add a like to a comment (clicking on ImageView) and notification to Firebase and also the user whose post it is gets a notification, and then another to remove it (clicking on ImageView again). Problem is that notification and comment both show up, and get saved to database, but then when I click again to remove the "like" the comment get removed from the database, but the notification doesn't.

Can someone help me out with the logic of this method. Something I am doing wrong because notification doesn't get removed only comment.

 private void likeComment(String commentId, String postId, String userId) {
        DatabaseReference reference = FirebaseDatabase.getInstance().getReference().child("Comments Liked").child(commentId).child(mFirebaseUser.getUid());

        mNotificationId = reference.push().getKey();

        HashMap<String, Object> hashMap = new HashMap<>();
        hashMap.put("notificationId", mNotificationId);
        hashMap.put("commentid", commentId);
        hashMap.put("userid", mFirebaseUser.getUid());

        reference.setValue(hashMap);

        HashMap<String, Object> hashMap1 = new HashMap<>();
        hashMap1.put("userid", mFirebaseUser.getUid());
        hashMap1.put("comment", "liked your comment");
        hashMap1.put("postid", postId);
        hashMap1.put("ispost", true);
        hashMap1.put("notificationId", mNotificationId);

        FirebaseDatabase.getInstance().getReference("Notifications").child(userId).child(mNotificationId).setValue(hashMap1);
    }

    private void removeLike(String userId, String commentId) {
        DatabaseReference reference = FirebaseDatabase.getInstance().getReference("Comments Liked").child(commentId).child(mFirebaseUser.getUid());
        reference.addListenerForSingleValueEvent(new ValueEventListener() {
            @Override
            public void onDataChange(@NonNull DataSnapshot dataSnapshot) {
                if (dataSnapshot.exists()) {
                    String notificationId = dataSnapshot.child("notificationId").getValue(String.class);
                    if (notificationId != null) {
                        FirebaseDatabase.getInstance().getReference("Notifications").child(userId).child(notificationId).removeValue();
                        reference.removeValue();
                    }
                }
            }

            @Override
            public void onCancelled(@NonNull DatabaseError databaseError) {

            }
        });
    }