When you leave Belgium, you are required to notify the government authorities of your change of address, either by recorded post or online. This way, the Federal Government Department of Finance can send a final tax statement to your home country.
For each year that you have worked in Belgium, you will receive a tax statement in the following year. So for a contract in 2015, you will receive a tax statement in 2016.
When you receive money from the tax authorities, they only deposit it on a European account. So make sure that you keep your Belgian account as long as you have ongoing business with the tax authorities.