Do I have to choose SMS receipt?

No, the SMS receipt is not something you have to choose, this is optional.

 

This is only an extra service we provide, if you want your order confirmation on SMS and not only on e-mail. Please note for most organisers do not accept the SMS reciept as a valid ticket confirmation, this is for personal book keeping.

You'll always get the order confirmation by email, but now you have the option to get it on SMS to.