I made a purchase at a store and received an email from the shop owner.
What level of respect/politeness should my reply be, in addition to using 丁寧形 throughout? For example, how should I choose between 〜てもらう and 〜ていただく? Should I use 尊敬語 and 謙譲語? Should I address the store owner as Xさん or Xさま?