Advice needed on job change - no HR work and more of 'money collection' work from the different clients of the company

Hi seniors and moderators, I am an MBA in HR and presently working as an HR executive in a construction company for the last 1 month. Earlier I had worked as a business development executive in an online shopping company for 3 months which was my first job. I had left that job and joined the present one because there I was paid 12000 and here I am paid 21000 p.m.
But after joining here I knew that there is less or no HR work and more of 'money collection' work from the different clients of the company. The thing is that I am not being able to learn anything here and I think I won't be able to learn anything here. And also threatens me saying that what he has learned in 15 years I have to learn that in 2-3 months otherwise, he will fire me. please suggest what to do?

Dear Vicky
With reference to your post and the situation you are in, it seems that you are dissatisfied with the role you are given. One option is to continue here, as financials are important and look for better opportunities at the same time.
The other option is to see if continuing in the same position, you can bring a few small changes or introduce HR systems and processes in your organization. When you introduce something new, learning will automatically happen. You have to see what space is given to you and what are the small HR process you can introduce which the organization will benefit from.
Challenges are in every sphere of life. You have a choice. Either run from the challenge or convert the challenges in opportunities.
regards

Thanks for the suggestion. I would like to tell you that doing something new is discouraged here. The manager is more interested in staffs' personal life than the company. You can understand.