my mum cut me out

Andrea • Est. 1994. Engaged. Mummy. Animal lover. Rugby lass.
I'm a 23 year old mumma, and I need some advice as I'm heartbroken! 
So I recently met my maternal grandmother and auntie for the first time.
My mum didn't want me or my sister to know our nan or aunt after my grandad and nan divorced back in 1993 and my aunt called my grandad a wanker. (Because he is a right tosspot, but I still love him regardless)
My mum said that my nan and aunt were nasty, vindictive, manipulative people, yet my mum can never seem to tell me why they are supposedly nasty etc. 
My Nan and aunt seem very normal, they tell me everything that happened during the divorce and it seems like a normal divorce. But my mum has cut me out of her life for knowing them. My mum has also cut her only grandson out her life too! Which breaks my heart! She's such a heartless cow, my mum lies about everything, she over exaggerates and quite frankly I don't believe anything she says. I simply don't trust my mum. But it still hurts after she told me to have a nice life! What do I do? This just hurts so much! 😢