Rihanna reportedly sent her loved grandmother off in a grand farewell celebration and now Rihanna has been hit with a grand ol lawsuit….

Clara Brathwaite  died in June, 2012.  Her body was sent to Barbados for burial, and Rihanna  wanted a party, complete with tents, multi-media large screens, huge exotic  floral arrangements — the whole kit and caboodle.

But parties/funerals  come at a price … and the company that threw grandma’s final shindig claims  the grand total was more than $150,000, and Rihanna paid only about a quarter of  that and refused to pay more.

The lawsuit claims Rihanna claimed the bill was exorbitant and she refused  to pay the balance.  The funeral home claims Rihanna’s demands came at a  hefty price.

So far no comment from Rihanna’s camp.