Can anything be done about my invoice?

Hi,

I have a complaint about the billing and this is also an inquiry about the possibility to handle the situation now. First of all, I'd like to say that customer service on your part is really bad. Despite highlighting the issue I received no communication upfront to provide help. On twitter and whatsapp, the feedbacks are non-specific. Your 1200 number is almost non reachable, and yes, I tried during accurate working hours.

Fornutaley, another number works and after about 25 minutes of wait I got hold of a representative who clarified the situation to me. I have a monthly bundle of about 10-20 Euros per month. Last two months I received invoices of about 100 Euros and more. I was in assumption that this is a miscalculated data usage due to eSim. But I am informed that billing is because of international calls. By mistake I used this sim to make the calls instead of the other one that I usually select. So I want to know if it is possible to make some concessions on billing since it was a mistake on my part. Secondly, I am told that billing also occured due to incoming international calls. I have never heard of this. Incoming is chargeable only when the user is roaming. Why am I being billed for receiving calls while I am in the home country Netherlands? This is unprecedented, but also has no mention of it during the customer om-boarding. I have gone through the details of new customer subscription, there is no mention of billing possibility of incoming calls, for any kind of call. Let me know if you ca make some change which can ease things for me. Because I can neither stop receiving calls, nor pay such huge sum.