whats a 'device of porting'?

Hi, I am asking for my sister

1.She is currently on Tunetalk Prepaid
2.She wants to port to Umobile Postpaid (GX50)
3.When request MNP through Umobile website it fails with Reason: Blacklisted due to outstanding payment with Maxis
4.Checking with Maxis Livechat, it appears that there were 2 unknown postpaid numbers having RM500+ in default payment. These 2 numbers are now inactive since 4 years ago. Suspected her IC might be used by unrelated parties. She asked for the latest bill (for reference and proof) but Maxis cannot do so as all records have been passed to Collecting Agency.
5.She is not keen to pursue for cancellation or any legal action despite me persuading her. She have never been contacted or harassed by the Collecting Agency.
6.Thus, focus now is to MNP from Tunetalk Prepaid to Umobile Postpaid despite the blacklist - Need your suggestions.

My plan, MNP from Tunetalk Prepaid to Umobile Prepaid. Then once successful, change plan from Umobile Prepaid to Umobile Postpaid. Or would using an agent help in smoothing out blacklisted MNP requests?

Will this work? Tq in advance.

This post has been edited by SerioseCat: Aug 5 2019, 09:33 AM