Change our flight time without any warning

I booked a flight to CPT next month and about two weeks ago my husband and I got a text to say our flight time has been changed, we really don’t have a huge problem with that but we need confirmation so we can arrange and plan better for our trip , I have Been calling your customer service number for the past two weeks and I wait in the line for more than 30 mins to no answer. Please can you get back to me urgently , this is really frustrating