I sent an invitation for my relatives (sister in law and her 2 sons aged 5 and 10) to come visit us in Canada, they collected all the documents IOM asked and sent to Moscow, Moscow refused to grant them visa saying the consent letter from father is not included.
Nobody warned them that this letter is a requirement for visa. We know that this letter is a requirement to leave the country but not for visa. I am not saying it is not, maybe it is, but if the document is missing from a package I would say the regular practice is send a letter and request it, not to deny the visa. Also please note that they said in the letter that they are refusing to give them visas, but they did not stamp their passports as denied. It' sad that now they have to reapply and re-pay the fees (in their letter they state this part).
Has anybody ever faced a similar situation? We invited lots of relatives to visit us, they all came and returned to their countries in 1-2 months, never violated any laws or something of that sort. Wonder why now we invite this particular person and she's being denied

I am insisting her to re-apply, but she does not want to pay fees anymore and has a suspicion that this consent letter was just a fake reason for them to deny to grant a visa. I am not saying she's right or wrong. But she just does not want to risk and loose another 3-4 hundred bucks.
Any thoughts?