Bank is playing silly buggers with guarantees; Can You Help Please?

My bank has decided to send me a nasty letter recently regarding a property i have.

Background…

i bought property A in own name in 1998 setting up a line of credit, then i sold prop A and bought property B in 1999; maintaining line of credit set up in 1998, with property B as security for the line of credit.

then in 2002 i sold property B to a trust with corporate trustee; where i am director of trustee company; maintaining line of credit set up in 1998.

as far as i was concerned all necessary paperwork for this to occur was done in 2002.

if there was something that may have been missed, it is not my fault but the banks responsibility; further i should not be made to suffer now if they had overlooked something at the time

now bank sends me letter telling me that trust has not gone as guarantor, as such in breach of something called national credit code
and that i cannot keep line of credit in my name;

The National Credit Code is Schedule 1 of the National Consumer Credit Protection Act 2009 which is after Chapter 7 of the Act.

Then information relating to Guarantees can be found in Part 3 (Related Mortgages & Guarantees) – Division 2 (Guarantees) of the National Credit Code

Questions I need some help with are…..

1) if bank did not get it right initially can they be nasty now retrospectively with legislation that did not come into being until many years later.

2) given the national credit code, does it apply for already existing loans, or is there some other existing legislation that past loan may have had probs with?

finally,

3) if the guarantee is from a related party, such as this instance, would this not mean that guarantee issues not really relevant, under the national credit code? (or am i missing something here?)

thanks again

yianni