Just two weeks into to her nearly yearlong jail sentence for fraud, the mom of four ran out of phone minutes and couldn't call daughter Milania on her 9th birthday.
"I was so upset, oh my God. That day I cried so much," Giudice tells PEOPLE exclusively in this week's issue.
"The officer said to me did you ever play poker before? I'm like, no and he's like you know when you run out of chips? I was like, 'Yeah,' and basically that was it."
For PEOPLE's full coverage of what's going on with Teresa Giudice and her family these days, visit PEOPLE.com/Teresa
Giudice, 43, was allotted 300 minutes to call her family per month but says between talking to her husband Joe, 43, and daughters Gia, 15, Gabriella, 12, Milania, now 10, and Audriana, 6, she could only stay on the phone for around 10 minutes per day.
"I didn't know how to check my minutes and how you run out and 300 go so quick," Giudice says. "So then I had to be without a phone for two weeks."
For much more from Teresa Giudice, plus an exclusive interview with her husband Joe as he prepares to serve his own prison sentence, pick up this week's issue of PEOPLE Magazine, on newsstands Friday
"I have never been away from my kids before and I have never missed any of their birthdays," she says. "I mean even in prison you can call your kids and wish them a happy birthday so he was just kind of heartless."