Changing interview dates

I've applied for universities and I've got an interview for all five (Whoop!!) but for two of them (Birmingham city and Portsmouth) I can't make it due to other interviews and a college trip to new york. I emailed them both back on the 12th January but I haven't heard anything from them since but before when I've emailed admissions about other things, they got back to me within 48 hours. Am I just being twitchy and worrying too much or should I ring them/email them again? I know it's a busy time for admissions right now but I can't help but worry

Give them a call on monday, sometimes universities might have a pretty full inbox so could take a while to get back to you. A phone call should hopefully get you an instant answer