Salam. You asked a good question and I admire your sensitivity to the Holy Month of Muharram. A refrigerator is a necessity especially for someone who needs to store a medication cooler than room temperature. There is no problem with buying something you need in Muharram, just try to do your shopping before or after the 9th (Tasua) and the 10th (Ashura). Those two days are when Imam Hussein AS and his companions in Karbala lost their lives and we should honor them by mourning.
Shi'as that look down upon you because of your name are probably unaware to the fact that the Imams named their children with your name as well.
You are actually doing us a great service brother. Many Sunnis often ask the Shi'a why we don't name our children and follow the sunnah of the Imams who named their children 'Umar, 'Uthman, or Aisha. You are helping us prove that we do indeed name our children the way the Imams named their children (although these names are indeed seldom heard nowadays). It's true that such names have negativity associated with them because of certain personalities in Islam's history, but they are also associated with some of the greatest personalities as well.
If you look at recent blog entries, brother Islamic Salvation has some great posts on 'Uthman b. Madh'un, a great companion of the Prophet. Imam Ali also named a son with your blessed name.
- Abu al-Faraj said: Uthman b. Ali about whom it is narrated from Ali that he said: I name him with the name of my brother Uthman b. Madh`un.