Not able to change the tariff from loop to prepaid s plan

Does this mean that I will keep on losing 99 cents everyday.

No. 

An option replaces parts of the basic tariff.

Example: If you buy the o2 my Data S, you have only a flat rate for the Internet and you no longer pay the EUR 0.99 for the Surf Dayflat rate. But you still pay 9 cents for calls and SMS.
If you buy the o2 my Prepaid S, you have a flat rate for the Internet (no 0.99 euro Surf Dayflat rate), a flat rate for calls (and you do not pay 9 cents per minute) and a flat rate for SMS (and you do not pay 9 cents per SMS )

Hello @vaisakh, thank you for your first post in our community 💙
Tearsbeforecrying allready posted alternative options. Are your requests solved with this help or do you still need any support.

kindly regards
Michael

I am trying to change my prepaid tariff from pack S to basic, but it always says it isn't possible to do it online and gives the option to call *107#, but I call that number and only shows my credits.

Hello @GRAZ123 ,
nice to read you here in our community. 💙
If you have booked the option o2 my prepaid s, you can deactivate this option in your Mein o2 Are on the website as well as iwithin the app. 
Please get sure that no pack is reservated when you top up your account, else this package will be automatically booked.
When you deactivate the package, or waited until the booking time is over, the package get lost and you will automaticalliy switched to the basic option. 

kindly regards
Michael

Hi Michael,

So what I understood is all that I need is to end the pack that I have and automatically the basic will take place, correct?

Hello @GRAZ123,

that is correct. The cancellation of your pack will be confirmed via text message.

Best regards

Giulia