System not working for credit cards...RIDICULOUS!

I have always used 2 of my cards for booking various shows and travels. But recently I have not been able to do so. this started in February when I was booking tickets for the CT Jazz festival. I could not do it without calling the call centre who each time have to start a new booking on my behalf. I have since battled with this when I was booking for The Grand White and now Trevor Noah and Bus tickets for my nephew last night and this afternoon. Please explain to me why we cant book at our convinience? Is Computicket service suppose to give us the freedom compared to wasting money and time on long phone calls that includes holiding on forever. worse case for me, I had to pay more because the tickets I book are no longer available when i speak to the consultant! this is absolute ******* and utter NONSENSE. Yes i am mad!!!