MTN Failed me

Good day To anyone who would be able to help ,i have been an mtn customer since 2018 October and in 2020 i took an upgrade at MTN Neecastle Mall store.I was assisted by Calvin Nitharn and during the upgrade process i asked if it would be a problem with the insurance if a different number is used on the new device and he said it would not be an issue as they insure the device not the Sim card.....in september the 12 i lost my phone and did all the things needed for me to submit my claim(I had been sent from pillar to post since september till November 13)They declined the claim because the number used on the device is not the number they issued to me,Their decline reason is something i asked about from they trained employee Calvin and he said it wouldnt be an issue but today am faced with continuation to pay for a device i do not have yet i had taken out insurance to avoid such but an Employee of theirs decided to only tell me what he wanted me to hear and nothing else.I would really appreciate if i could be helped to get my phone replaced as it is not my fault that their employees are incompitent and disclose of information only they want us to know.If they can not replace the device then atlest they should cancel the contract as their employee was at fault here and not me.My contact number is *** and email adress is *** /*** Kind regards