Welcome back to the Wefugees Community and thank you for reaching out to us.
First of all, I am happy to learn that you managed to get the citizenship and to solve the related issues. Really sorry though that you are struggling with the authorities again now - this time about a visa for your mother. I can understand your disappointment.
As you know, we are not lawyers at Wefugees and can not provide legal advice in that sense, just share our knowledge and experience. As far as I know, you can appeal against the negative decision immediately but also file a remonstration (complaint) within four weeks after the rejection in the first place. This may be the cheaper and faster procedure. In case the remonstration will get rejected, there is still the option to appeal in court. I am afraid that you should try to add more proof/explanations why your mother is definitely not planning to stay in Germany but will return to Pakistan to convince the authorities.
Maybe a counselling centre or a lawyer can be helpful here.
Can you add any advice/information dear @mbeon-fardeen?
@muhammadshoaib1811, please don't hesitate to keep us updated or to get back to us with any further questions.
All the best,