Mixed signals during career talk

I'm an Accounting Manager at an admin firm for almost 4 years. Our company has been recognised for 10 years now as the best administrator in terms of employee engagement, client retention and business growth. It is a great company with a great salary package, not to mention with great people to work with. My only issue now is that I feel I have been doing the same thing for the past 3 years and I feel like I'm not growing technical-wise or soft skills-wise. I'm just taking on new client engagements that don't give me the stretch that I'm looking for. So I went to my line manager (who was just recently hired by our Country Head) and raised this with her. Unfortunately she wasn't as helpful as I wanted her to be - she advised that I continue doing what I'm doing since that is my strong suit and maybe one day, our Country Head will take notice and promote me to the next level. Obviously I wasn't satisfied, so I went to our Country Head and told him the same thing. And he said I'm not ready to progress because there are other areas he feels I haven't applied myself to yet (and he said this after saying there's no tickbox exercise to get promoted, you get promoted based on merit). I explained to him that its not helping me with my career prospects if he has a different expectation of me from the ones set out by my line manager, but he said to just trust her and to work with her to set out my new career objectives. He also offered to review it once we're done. He also mentioned that I should be doing what my line manager is doing since the position I'm aiming for is actually my line manager's. This confuses me even more because why does he need two people doing the same thing? Plus I think my line manager won't welcome the idea of me trying to take on her job especially when she's newly hired and is just beginning to establish herself within the team and with the clients. Did this ever happen to you? What did you do in this type of situation?