Checking your tax bill is always a good idea, writes Marc Quaghebeur. Appeals should be made in writing within six months of the date the assessment was sent, so don’t waste time.

Oh no, the brown envelopes have started arriving. You file your tax return in June and usually the bill only comes in March or April of the following year. This year the envelopes are dropping on doorsteps earlier than ever, bringing with them that gnawing feeling – how much do they want this year? Sometimes that feeling turns into shock. They cannot be serious. Surely that must be a mistake…It is always a good idea to double check.

Sometimes, you get an advance warning that things will turn nasty. The taxman sent you a letter saying that he really cannot accept the figures in your tax return. He had given you a month to reply. You went over your records, and you sent him a long explanation that your figures were correct. And then, all you received was a letter from the taxman saying that he sticks to his position, and here, now, is the brown envelope with the bill.

You do not want to leave things like that. To set the record straight, you need to file a reclamation or bezwaar. This means that you must protest in a letter: not by fax and not by email. The letter has to be sent to the address of the tax director that you find on back of the tax bill. Make sure that you mention all the relevant references. When in doubt, attach a copy of the tax bill. This starts an appeal procedure with the tax authorities. You cannot go to court before doing this.

What is important is to set out in detail why you do not agree. Maybe you forgot to mention a figure in the tax return, or the taxman overlooked a figure. All your expenses really are business expenses. Or the taxman wrongly considered a particular type of income as taxable. It is also advisable to ask for a meeting with the tax director. It may help to get your point across. Finally, don’t forget to sign the letter. If your assessment is also made in the name of your spouse or partner, then both of you must sign.

Most importantly, don’t waste any time. The letter must arrive within six months of the date on which the assessment was sent out. That date is stated on the assessment. Preferably send the letter by registered mail. If you have waited until the last day, you can bring it to the tax office and ask for a stamp confirming the date of receipt on a copy of the letter. Don’t forget that for the taxman close of business day is 4 pm. And if you find the door closed, you can try and send it by fax; you never know, the taxman may accept it.

Six months seems a lot, but it may pass quickly. If you are too late, your complaint will be rejected, except in some cases. Sometimes the mistake is so obvious that it would be inequitable if the taxman did not correct the tax bill. The tax authorities are allowed to reopen the tax file up to three years later for typos, miscalculations or obvious mistakes. Another reason for the taxman to reopen the file is when you have paid tax twice; in particular if you paid tax in Belgium and in another country.

You can also ask the taxman to reconsider when there are new elements that you could not show before. Not everything is a new element and certainly not a change in the law. Case law of the constitutional court or the European Court of Justice may be new information. But if you are told there will be new case law that could support your case, the safe bet is to file your complaint within six months.

The good news is that you do not need to pay the tax you challenge. Of course, you need to pay the tax that is due. That is the tax on the income that you declared or on the income on which you have agreed to owe tax. The tax director should let the tax collector know how much tax is due on that income. But sometimes the information does not pass and the tax collector keeps asking for the tax.

The tax director has six months to take a decision. After six months, but not a day earlier, you can take your case to court. That is not always advisable and most taxpayers wait to see if the director will agree. You never know.

If you get tax back, sometimes years later, you will get interest. At 7% per year, that is a good investment, and it is tax-free.