Language school claiming money from me (Frankfurt)

Hello,

A language school is demanding money from me for a B1 course I expressed interest in. I agreed to their terms and conditions but as they stated .

Registration
There are following options to register for an EVOLANGUAGE Training:
1. The registration should be made via online booking, sent by post (Postal address:
EVOLANGUAGE Kaiserstr. Protected content ) or by e-mail:
Protected content .
2. You have the choice of either paying the course fee with a check Protected content
processing fee), via transfer (untill 14 days before the course starts) or in cash
on your first day at school. Any bank charges applied to payments or refunds must
be paid by the participant. The participant is obliged to pay the tuition fee at the very
latest prior to the start of the first lesson.
• You pay the total cost at the time of booking.
• You pay a deposit of 150€ to secure your booking at least 2 weeks before the
course begins and you pay the course fee in cash at the school on your first
course day.
• The registration fee is 45€.
Withdrawal and Cancelation
1. In cases of withdrawal from a booked course prior to the course start, the language
school will retain the following amounts of course fees:
Withdrawal up to …..
• 14 days before start of course 20% of total fees
• 10 days before start of course 30% of total fees
• 5 days before start of course 50% of total fees
• after course start 100% of total fees
Evolanguage recommends taking out a cancellation-of-travel insurance.
2. Please note that the registration fee of 45€ is non-refundable.

I never paid a deposit or registration fee as they seemed unprofessional to me as they demanded money right away before a qualification test.

Anyway they refuse to have any dialogue with me and only keep sending me bills and now they have passed it to their payprotect internet provider.

Does anyone have any good lawyer suggestions, the bill is up to Protected content now.

thank you