7/1972 unfranked Danish airmail sent as surface mail & taxed; unpaid then paid

1972 incoming Danish taxed mail - unpaid, then paid: 25 JUL 1972 airmailed EL-AL stationary picture postcard of Israel from COPENHAGEN to HAIFA (with Hebrew message dated a month earlier), posted unfranked and stamped by "airmail fee unaccepted" French cachet; as such dispatched by surface mail, arriving Israel where taxed 0.40L using 1969 2nd Town Emblems Ba430 frank; apparently as unpaid, annulled with "difference not paid" crossed handstamp (this scarce), but when addressee came to pay, new 0.40L frank applied (different hue/slight shift) and cancelled by 23-8-72 HAIFA-60 postmark & next day HAIFA-36 delivery postmark on original postage due frank.