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With over 100 contacts to delete, I can see how having a select all option would help speed up the process.
Regrettably, I do not believe Blackberry still supports the Blackberry 10 OS as they have moved on to using the Android OS so this functionality will remain the same.
I was a Blackberry user for a long time but a few years ago I made the switch to Android and have been quite satisfied. If you are considering a new device, feel free to ask the Community for their advice on what device you should get next!
I have some advice.
When you add an email address to your device weather it be a Blackbery Q10 or an Android or an iPhone, the email. contacts, and even calender entries are syncd to your device, but they also exist online on the email server for example, gmail, yahoo, hotmail, outlook.com, if you sign in to your hotmail or what ever email you have via the web portal, you can view and delete your contacts in bulk and guess what, the changes will "sync" with your handset and its done instantly
why waste time trying to delete bulk contacts from your device when you can do them from your email portal, its faster and more efficient.