Liberty Life - not living up to their undertaking

I feel that I have been treated unfairly by LIberty Life - when I took up my LIberty Life policy more or less two years ago I made the necessary declaration with regard to my mother's breast cancer on which I received a one-year exclusion, which I accepted. However, this exclusion was subject to submission of a clean mammogram the next year and I understood it to be a run of the mill exclusion until proof of mammogram is provided whereafter I would receive this cover accordingly from thereon. <br> Although I have provided a clean mammogram Liberty is not delivering on this undertaking and do not want to lift the initial exclusion. I feel that they are not treating me fairly and is discriminating against me due to the cancer my mother had when she died. The mammogram I have provided does not show any risks, which the radiologist verbally confirmed with Liberty - they are penalising me in order to avoid carrying any risk in this regard. I would really appreciate a clear reason why this seem to be the case.