Airlines and tour companies are usually not obliged to give refunds on travel warnings. After all It's not their fault. The only exceptions are if they are unable - or unwilling - to actually provide the services you paid for, for example it's so dangerous they won't fly to your airport. For any other circumstances you are expected to claim from your travel insurance if you have it.
Travel insurance usually covers cancellation for terrorism and such like. However there will be clearly defined circumstances when you can claim which should be in your policy. A common condition is that there has to be official government advisories against traveling to the specific area you are going to. Different governments have different advice. Canada has no advisories for Turkey (though it does suggest caution) and the US only advises against visiting south- eastern Turkey. It's unlikely you will be able to claim for any travel other than that region.
In the end It's your insurance policy that controls when you get a refund. Read it carefully and if you genuinely think you are due a refund according to policies talk again to your insurer. But not getting a refund in the circumstances you describe is very normal.