Public relations / Marketing

Im not sure if you can help me In 2015 i got a mentor from a goverment agency to mentor in my business which was struggling he came to me for one visit and then ended up resigning as mentor and then asked me to sell the business to him i agreed after a while and the deal was struck up i was to be retained as the operations manager and he was going to be like an investor and I was going to continue what I was doing ie the day to day running of the business from the start when he became the new owner it was very difficult and it was like he had a resentment at me and never really let me be the operations manager he constantly put me down in front of staff and customers and treated me very bad until finally dismissing me in july of last year I now have set up a new company Graphic Print and Signs and am beginning to contact all the previous customers now why im telling you all the history is that i need a pr marketing plan in how to get back in with all the customers and what story to spin them as it doesnt look good if i just sold the business and to be back in in the same business i need to win there sympathy and loyalty no doubt he has probably spread all sorts of malisious rumours about me to discredit me i need to get the majority of those customers back can you help me and what do you propose before we sign up together