The reality TV star hit back at the alleged friend on Twitter yesterday (14 July) after the TOWIE gang, including James 'Arg' Argent, Jess Wright and Joey, had all spent the afternoon at Wireless festival in Stratford, London.
Joey - who broke off his engagement to Sam in Marbella in June - was spotted having fun in the VIP area of the festival with co-star Arg and at one point, he was caught kissing a mystery brunette.
However, Sam doesn't appear to be too pleased that Joey has moved on, especially given that she apparently grew up with the girl he was seen smooching.
After news broke of Joey's kiss, Sam tweeted a link to an article that included pictures of her ex and the brunette together and wrote: "Known this girl since I was 7, just shows u..."
Soon after writing the tweet, she also re-tweeted a quote that read: "Dogs have no morals...", as well as another quote from a parody account made for American rapper Drake, which said: "Over thinking does kill your happiness."
Meanwhile, Joey seemed to be too preoccupied with having a good time at the festival - which was headlined by Jay-Z and Justin Timberlake - and tweeted afterwards: "Just left wireless !! So good. Thank you!!!"
But despite hearing about her former flame getting close to another girl, Sam still appeared to have had a blast at Wireless and uploaded a photo of her enjoying the day with sister Billie and co-star Jess Wright.
She captioned the snap: "This was before it all went wrong ..."
Joey and Sam got engaged in Dubai earlier this year, before Joey decided to call an end to their relationship during the group's annual holiday to Marbella last month.
In the series nine finale of TOWIE (which aired last week), the young Fusey boutique owner admitted to Sam that although he missed her, he was happier now they'd split.
What do you think of Joey moving on? Is it too soon? Let us know below!