Teen singing star Joe Jonas is denying cheating on ex-girlfriend Taylor Swift, putting the break-up down to "a change of heart." Jonas has came under fire recently after Swift revealed he had ended their relationship in a 27-second phone call and accused him of dumping her for "10,000 BC" actress Camille Belle. But Jonas Brothers singer is hitting back, and is adamant he was never unfaithful to the sexy country singer. He writes on the band's official blog, "I never cheated on a girlfriend. It might make someone feel better to assume or imply I have been unfaithful but it is simply not true. Maybe there were reasons for a breakup. Maybe the heart moved on. Perhaps feelings changed."And Jonas insists that the reason their break-up conversation took place in less than 30 seconds is because Swift slammed the phone down on him. He adds: "I called to discuss feelings with the other person. Those feelings were obviously not well received. I did not end the conversation. Someone else did. Phone calls can only last as long as the person on the other end of the line is willing to talk. A phone call can be pretty short when someone else ends the call. There were later attempts at communication that had no response."I wish the best for the other person but could not sit back any longer and leave our fans with a wrong impression of the truth."