Help with my grandparents, don't know what to do?

For years my grandma has been a drama queen and piled lies upon lies - she once blurted out in an argument with my mum (she is my dads mum by the way) that she had bowel cancer infront of me and my sister baring in mind we were only young. This turnt out that it wasn't even true? I don't know why they are like this, I know their hearts are most of the time generally in the right place but I had a big fall out with them over a year ago and decided I didn't want them to be a part of my life anymore - i know it sounds selfish and horrible but they can be selfish people. They came down to where we live and during their stay my grandma apologised to me but my grandad never did but i decided life is to short to hold a grudge and they are my family. They live over 2 hours away and they rarely bother to come down to see us - i know they are old but they are capaple to drive and are in good health ect. I just feel they make no effort whatsoever. When i had this big fallout with them i was shocked my dad took their side and didn't stand up to my grandad. I know it's hard because they're his parents but he lets them walk all over him. They call my younger brother James because they don't like the name Jamie and it winds me and my mum up so much - she has pointed it out to them so many times so i know its clearly not a mistake yet my dad will never say anything? I can't really talk to my dad about it because it always ends up in an argument. My mums dad (my other grandad) died 3 years ago this year and he was the most generour, kind hearted and loving man you would ever meet and i would do anything to have him back yet my grandma is constantly moaning about what is wrong with her life, it makes me angry as for her age she is in perfect health and should be happy she is still alive. i really don't know if i want contact with them anymore but just wondering if anyone has any advice - sorry its long and thankyou for taking the time to read it all X