The 25-year old Senegalese striker has been in London trying to complete a transfer to West Ham United but his attempts have been blocked.
Ba feels that Hoffenheim gave him the all clear to depart the Rhein-Neckar-Arena but have since gone back on that promise and are now trying to thwart his move to Upton Park in what he believes is unfair treatment.
"I know what I owe to TSG 1899 (Hoffenheim). They brought me to Germany and they believed in my potential. They helped me improve and be a good player in the Bundesliga. For all of that, I thank them," he wrote on his official website.
"I also know that, with my team-mates and the support of our fans, I had the chance to give back a lot to my club by scoring a lot of goals and being a major player in the good performance of the team.
"Today I am one of the oldest players in the team and, due to my seniority, I refuse to be treated like a mercenary or a capricious guy.
"I want to say that I regret this situation, and I suffer from it. The club gave me a green light to leave under certain conditions, which have been met; I hope that the promises made will be fulfilled.
"I just want to ask my club to be honest and to respect the green light that I was given."