The Duchess of Sussex told her father he had "broken [her] heart into a million pieces" for causing her "unnecessary and unwarranted pain" in a heartfelt letter.
The 37-year-old former actress - who was known as Meghan Markle before her marriage to Prince Harry - penned a five-page note to Thomas Markle last August, in which she complained he had made no attempt to contact her, rebuked him for giving interviews claiming he had been shunned, turning down their help and siding with her half-sister Samantha Markle with her "vicious lies", who she "barely knows".
Thomas insists he wanted to keep the letter private "out of respect" for his daughter, but has now made it public following recent reports about its contents.
In one extract, obtained by the Mail on Sunday newspaper, Meghan questions why he told the media he had been in touch to tell her wouldn't be attending her and Harry's wedding after suffering a heart attack, because she didn't receive a call from him.
But he told the publication: "I sent Meg and Harry a text telling them I wasn't coming. It was too dangerous after my heart attacks."
The former 'Suits' star went on to discuss how "horrifying" it was to learn about his heart attack from external sources.
She wrote: "I have only ever loved, protected and defended you, offered whatever financial support I could, worried about your health...and always asking how I could help.
"So the week of the wedding to hear about you having a heart attack through a tabloid was horrifying.
"I called and texted. I begged you to accept help - we sent someone to your home... And instead of speaking to me to accept this, or any help, you stopped answering your phone and chose to speak to tabloids."
The retired lighting director again defended himself from Meghan's claims.
He explained: "I didn't stop answering my phone. I was in hospital with a heart attack! Meg and Harry knew what was going on."
Meghan also hit out at her father for publicly criticising Harry, despite the prince being "nothing but patient, kind and understanding" and begged him to stop "exploiting" their relationship and "fabricating" stories.
And she insisted Thomas had done nothing to try and get in touch with her, despite his public claims she had rejected his attempts.
She wrote: "You haven't reached out to me since the week of our wedding, and while you claim you have no way of contacting me, my phone number has remained the same.
"This you know. No texts, no missed calls, no outreach from you - just more interviews you're being paid to do to say hurtful and harmful things that are untrue."
Thomas, 74, branded Meghan's lengthy letter a "dagger to the heart" and dismissed her claims, showing the newspaper texts he believes prove he'd made attempts to communicate with his pregnant daughter and her spouse.
He said: "I thought it would be an olive branch. Instead, it was a dagger to the heart."