In a non-refundable ticket, when you get it cancelled than you may only get "refund" of taxes for a totally unused ticket. (Please note there are lot of fare rules and their combination not possible to list all but this is usually the case).
Sometimes if a ticket, if non-refundable after departure, is shown as non-refundable online even if it is refundable before departure.
In your specific case it seems you cancelled the ticket before departure, therefore you got refund. With OTA (Online Travel Agent) you get refund which is not bound to any airline but dealing with airlines usually they give you credit shell with one year validity to be used with the same airline. But in both cases, usually, you can ask for full refund.