Why cant FNB profile be transferees to a new cellphone?

I bought a new i phone and therefor want my FNB bussiness account profile to be transferred to my new i phone( from my old i phone). I couldnt manage to donit online. I went in to FNB in George but they couldnt help me but phone the call centre and gave me a computer to go internet banking. The lady took me through various processes for 1,5 hrs and I could then acess the account. A few days later at month end I had to approve a few trabsactions, but I couldnt as my 4 digit pincode wasnt accepted. No one told me that it should be changed, they said the sign on and password remains the same. So the system then was blocked. Went back to FNB in George. Again on the vomputer eith the telephone to the call centre. Big problem, now the other account holder must also ho on his computer, he is 1200 km away. I walked out of the bank. Why if I change cellphones the other signatory to be involved, it has no impact on the account. Its made extremely difficult for Ni apparant reasons. I have accounts incl bussiness accounts with two other baks and I have changed the progiles within 5 minutes safely to my new phone. I dont understand why FNB is so difficult, and no one can really help. Very unhelpful staff and I have talked to 4 different people.