to build a station

ok, haven base has been destroyed, and i have gotten the hoard and a capsule drive. but i had not completed the ‘to build a station’ mission before i did all the prior. so now i have gone to the maas sation, taken a cargo of station supplies, and by mistake called jaffs in to pick them up. since i don’t know how to unselect cargo once i havee already told jafs to pick it up (can u even do this?) i had to fly back home, add it to my cargo launch list, and then fly it to the hoffers gap trading post. now that i am their with it, i approached the post, undocked the cargo, and docked with the station. nothing happened. so, i saw the blue foreman craft, and flew up to him, undocked the cargo next to him. nothing. no responses, no apparent way to end the mission. and no new emails or mission objectives at my base when i got back.

what to do?