Mojang customer support operates Monday through Friday, and has staff in both Sweden and the US. We usually answer emails within 1-2 business days at the start of the week and within a few hours towards the end of the week, as shown below:
To ensure that we can help you as quickly as possible, please be sure to include all requested information when contacting us, and send your issue just once. If you receive a response from Mojang, please reply to that email, and it will bring it to the attention of the staff member who was helping you. We appreciate your patience, and look forward to assisting you soon.