General ACCAACCA Per - qualified accountant to sign off

Hi I had a frustrating experience in getting my Per to be counter signed by a qualified accountant and I would like to ask for advice. My time experience was signed off by my non-qualified line manager , however she could not sign my Per. I requested permission from my company external auditor with my company managemt’s consent but was flat out denied by them due to an excuse that the audit firm partner does not know my work. I repeatedly inform them tHat they can contact my line manager for verification but they still refuse to do so- it’s been almost a year of waiting till I get the definite ‘no’ answer. Now my question is can I appoint another qualified accountant to sign off my work even thought he does not have any business interactions with my company? He’s willing to contact my line manager and confirm my work. I contacted Acca regarding this and they were very vague about this but confirm to me that a qualified accountant is eligible to sign. Please advice.