Britney Spears' father believes she has only herself to blame if she loses custody of her sons and fails to revive her career. James Spears has written an open e-mail to her former manager LarryRudolph - who the singer fired last Friday - apologising for her behaviour and thanking him for all he tried to do for the singer. Britney's dad wrote: "When Larry Rudolph talked Britney into going into rehab, he was doing what her mother, father and team of professionals with over 100 years of experience knew needed to be done. She was out of control. Larry was the one chosen by the team to roll up his sleeves and deliver the message, to help save her life."The Spears family would like to publicly apologise to Larry for our daughter's statements about him over the past few weeks. Unfortunately, she blames him and her family for where she is at today with her kids and career. Larry has always been there for Britney. For this, we will forever be grateful to him."Britney has responded by saying her father has never understood her. In a statement released through her representative, she said: "I am praying for my father. We have never had a good relationship. It's sad that all the men that have been in my life do not know how to accept a real woman's love. I am concentrating on my work and my life right now."The 'Toxic' singer was reportedly ashamed she had to go to rehab to protect her public image on Rudolph's advice, when she felt she had no addiction problems. A source told the New York Post newspaper: "She had no drugs in her system when she was admitted to Promises - they ran tests and there was nothing. She was embarrassed she had to go in there when she knew she was suffering from postpartum depression, not a drug or alcohol problem."Britney's aunt had just died of cancer. She was feeling very guilty because she hadn't been there with her, she was over whelmingly depressed and she shaved her head in solidarity."