My mother died and she wasn't satisfied with her brothers. Now if I get the full story about the problem and find out that she was right in her stand what should I do? Do I forgive my uncles or not?

Praise be to Allah, the Lord of the Worlds; and may His blessings and peace be upon our Prophet Muhammad and upon all his Family and Companions.

It is unlawful for you to sever relations with your blood kinship including your maternal uncles because of what had taken place between them and your mother regardless of whether your mother was right or wrong.

Know also that severing blood kinship ties is forbidden. Allah Says (interpretation of meaning): {Would you then, if you were given the authority, do mischief in the land, and sever your ties of kinship? [8] Such are they whom Allah has cursed, so that He has made them deaf and blinded their sight. } [47:22-23].

The Prophet (Sallallahu Alaihi wa Sallam) said: After Allah finished creating human beings, Rahim (showing kinship to closest relatives by blood relations) stood up and said: “This is the rank of those who seek refuge with you from severing kinship ties”. The Lord said: “Yes, Wouldn’t you be satisfied that I keep ties with those who keep your ties and sever ties with those who sever your ties?”  She said: ‘Of course’.  He said: “That is for you”. [Reported by Imam Al-Bukhari and Muslim].

Assuming that you had some conflicts with your maternal uncles, you should never sever your kinship ties with them.  Rather, you should – as you mentioned – forgive them and should forget about all the problems you had with them.

It is reported by Muslim that a man came to the Prophet (Sallallahu Alaihi wa Sallam) and said: O! Messenger of Allah, I have relatives (to whom I show kinship and they do not show any kinship to me.  I do well to them and they do badly to me.  I forbear their bad acts and they offend me.  He (the Messenger of Allah) said: ‘If you are as you said, it is as if you were making them eat ashes and Allah will back you against them as long as you are on the same way’. 

Allah knows best.