Mobile
Your €29 monthly plan includes 22 GB of data per month. Converted, that is 0.7 GB of data per day. So during the seven-day transition period before your first bill, you can use approximately 4.9 GB (0.7 GB x 7 days). The price of your monthly plan for those seven days is also prorated (€29 / 31 days = €0.93 per day for 7 days).
Internet:
Suppose you ordered limited internet? Then you pay €27 for 300 GB per month. Converted, that is 9.7 GB of data per day. So if you get your first invoice seven days after activation, for example, you can use approximately 67.2 GB (9.7 GB x 7 days). The price of your monthly plan for those seven days is also prorated (€27 / 31 days = €0.87 per day for 7 days). Did you also order Wi-Fi boosters? Then you
are also charged the price for that hardware, this one time only.