Praise be to Allaah.
If you are full siblings of the deceased or siblings through the father only, then the division of the estate that was done is correct and there is nothing wrong with it.
But if you are siblings through the mother only, then there is the issue of kalaalah, which may be explained as follows:
1. If a person dies and leaves behind full siblings, then the estate is to be divided among them with each male getting the share of two females. There is consensus among the scholars on this.
Ibn Abd al-Barr (may Allah have mercy on him) said: With regard to the words of Allah at the end of Soorat al-Nisa' (interpretation of the meaning): if there are brothers and sisters, the male will have twice the share of the female [al-Nisa' 4:176], there is no difference of opinion among the earlier and later Muslim scholars that inheritance of siblings through the mother only is not like this. Therefore they are unanimously agreed that the siblings mentioned in this verse are siblings of the deceased through the father and mother (i.e., full siblings) or through the father only.
End quote from al-Tamheed, 5/200. See also al-Mughni, 6/162
2. If a person dies and has no father or child, and he leaves siblings through the mother, this is a case of kalaalah. If there is only one brother through the mother, he gets one sixth. If there are more than one, they get one third, which is divided equally between males and females. This is one of the cases in which the share of the female is like that of the male.
If we assume that you are siblings of the deceased through the mother only - and you are not full siblings - then you take one third of the estate and divide it among you equally. If she had no other heir, then the rest of the estate comes to you, so the estate comes to you through allocated shares and by default, and it is to be shared equally among you.
And Allah knows best.