Tried KuaiDial for iOS7&8. Seemed to only send a busy signal when the number is placed in the whitelist with Whitelist only setting. Putting the number in the blacklist and setting it to Blacklist just lets it ring. Seems backwards, doesn't it? Also tried SMSNinja which didn't block the number. any other free alternatives which send a busy signal. Parents' iPhone 4 is getting bombarded with telemarketers.