Update:
I finally got reply from the manager, Maxime, after he reviewed my case, he helped me right away, and respond my email within a day.

and now my zendesk works perfectly.

I changed my rate from 1 star to 5 stars, all because Maxime's help.

If you are looking for customer services app on shopifty, Zendesk is the best choice, and if you have low budget, you always can start at as low as only $1.

you wont regret.

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Like the concept of Zendesk,
But i cant install the zendesk with my shopify and contacted with support team almost a month. But i did not hear from them for almost two weeks.
supper disappointed.
Do not waste your time to deal with them.

Zendesk is nice. It's easy to reply to Facebook, Twitter and emails on iPad, iPhone, android device and desktop. And especially cheap for first one year.

Zendesk is amazing. Great support. Use the voice feature also for calls.