How do I dispute a bank loan, which I signed for, but did not use the business credit card,another did and did not make any payments.

If you suspect identity theft you should contact the police and get a police report and then report this to your insurance company to resolve on your behalf.  If you know the individual who used the card without your permission you should sue them.  Understan that this individual is likely to be prosecuted, so if you do not wish that to happen you better work out a settlement agreement.