Your issue does not seem to be completely related to hearing. A first step would be to rule out hearing dysfunction with a hearing test. After which, a discussion with a physician as well as an exam to check on various nerve function would be appropriate. Somethimes our inability to comprehend or create speech is due to anatomical or neurological impairment. However, in your case, starting with a hearing test and a physician exam would be the best recommendation. Good luck.
Is your voice soft, sometimes people are not listening. Is it when you are on the phone this could be a contributor? Look at the person talking to you or when you are talking to them make sure you have their full attention. Have your mom's ears checked sometimes it could be the other person not you. Have your sinuses checked if you are having sinus pressure it can cause difficulty hearing. It is easy for people to tell you they didnt hear that so when it is not done they can tell you they didnt get that message, so the fault is going to be back on you. Write down what you told them, date and time do follow ups that way you can put your mind at easy.