I lived in a country which signed a Convention with Israel. I continued to pay national and health insurance contributions in Israel according to my incomes. Am I entitled to reimbursement of the insurance contributions I have paid during that period?

First, a distinction shall be made between national insurance and health insurance. 
Health insurance is not within the scope of the conventions, and therefore, you had to keep on paying health insurance contributions in Israel according to your incomes.

However, if you were insured by the convention country's Social Security Institute, we would examine whether you may obtain reimbursement of the national insurance contributions you have paid in Israel. To that end – you have to provide the branch of the National Insurance Institute nearest your place of residence with authorization pertaining to the periods you were insured in the convention country.