What is an international freephone number ? , not every country has the same format for ‘freephone’ numbers , and for any one business to arrange that the same number called from anywhere in the world would be ‘free’ would be a logistical nightmare, assuming it were even possible.
If an American company has a free phone number in America for its employees or customers , that’s pretty standard business practice, but the fact that they use the term ‘call collect’ ,for an apparently available option to call from other countries without charge , when that’s an Americanism and is not a term used by UK Telcos , ( presumably the UK equivalent is a ‘reverse charge’ call ) , where the UK operator places the call , after confirming the recipient will accept charges, with the proliferation of communication providers and network providers , I doubt there is any requirement to offer ‘reverse charge’ calls .
If there is a freephone number that works internationally , the American company would need to make an arrangement with all possible providers in every country, as they couldn’t possibly know what network the caller would be using .
There was ( maybe still is ) ‘0800 reverse’ , but that isn’t anything to do with BT and I have no idea if it works for international calls .
TBH , the OP simply made an error and made an intentional call , incorrectly assuming that there was some billing alchemy that meant it wouldn’t appear on their bill , if their American employer has made arrangements to enable their staff to call ‘head office’ for ‘free’ from anywhere in the world , they apparently haven’t taken the time to explain how to access this service successfully.
