I'm an immigrant (UK > NL) and don't see how you can give anyone blame here except for the BD being inept and the gastouderkantoren committing fraud. The systems here are complex and there are a lot of really dumb rules (like a flat on savings based on a 4% interest rate - instead of the earnings being treated as flat income as in other countries).
Taxes are very hard for non-natives, they use a formal style of Dutch which can be hard for people still learning the language.... and learning a language if you have small kids AND WORK(!!) isn't easy (for me it was very easy but I didn't have kids then and I'm in the top 0.1% of intelligence if you believe that such test aren't BS).