After a bid has been placed no details may be changed. As you did not state a clear end time before the first bid default rule comes into place. Many thanks for your understanding
6.2.5 Each domain and website auction must have the required information: domain, registrar, expiration date if rule 6.1.6 applies, starting bid (default: $1), bid increments (default: $1), specific end time (default: 72 hours after last bid), and payment options.