I recently traveled to Kenya and back to NYC via Delta's partner Kenya Airways. Realizing after my first flight over that I had a deep discount economy ticket that would only give me 25% of base miles, I decided to pay for an upgrade to a business class ticket on the return flight (my ticket shows a Z class ticket, which the website says is worth 100% base miles) so that I would be sure to reach diamond before the end of the year. (Background, I was a million miler/exec platinum on American and have been loyal for 20 years and did a loyalty swap this year to try Delta for the first time. I make transatlantic flights at least monthly so having the highest status and benefits really makes a difference with ease of travel). After returning from Nairobi, I noticed my miles never posted, so I called (twice because they didn't do it the first time) and both times they said they'd fix the error and, the second time I called, she confirmed with a Skymiles colleague that I should expect to receive a total of 9198 miles for that trip (25% of miles there, 100% of miles back). They showed no ambiguity in confirming those miles. It was consistent with what the website says (business Z class tickets get 100% base miles). I called a week later noticing that only 25% of my return flight miles were posted. The person I spoke to then spoke to the relevant people at the Skymiles desk again and confirmed there had indeed been an error and that I should check back in 24 hours at which time I should see 100% of miles for the return flight from Nairobi. Again, no ambiguity in the represented outcome. They were VERY clear that I was entitled to 100% base miles having upgraded my ticket to a Z class business ticket. Then I noticed the next day the change still hadn't been made. I called back and the fourth person I spoke to suddenly said I was NOT entitled to 100% of the miles for the return flight. That Kenya Airways had somehow only processed my upgrade as an "upgrade" rather than a "ticket change" and that despite my ticket showing a Z class on it, they said the info sent to Delta showed an R class (no change from my original ticket) despite my having paid $1000 to upgrade the ticket for the express reason of getting more miles on my return journey at their suggestion. They suddenly said there was some technicality and I am not supposed to get the miles unless I had booked the ticket differently. Mind you, this is the fourth person I spoke to. Then, when that person brought on the supervisor to review the issue, she fully agreed with me that all representations made to me online and over the phone pointed to my getting 100% of base miles and Delta SHOULD honor their word. but, unfortunately, she doesn't have the authority to do anything about it and, best case, I can either spend around $3500 to buy the extra MQMs needed for diamond status (because I was short nearly the exact amount of the differential I'm disputing, 5,800 miles or so) or they could put in a request for an exception with corporate after Jan 1st but there's no guarantee it will be granted. She noted she would make copious notes suggesting Delta SHOULD do right by their word and fix the situation. She even suggested that I call back and ask again the next day (because we're coming upon the cutoff to travel) and I did and the person now stated the same as she did but that he couldn't do anything to fix the situation himself. I am a very frequent flyer and I really feel it isn't right that Delta misrepresents information on their website and through their customer service reps and then doesn't stand behind those representations, whatever representations are made. It is way beyond reasonable to assume that I would have known, after being told otherwise, that an "upgrade" to Z class wasn't the same as buying a Z class ticket for the return. My ticket says Z class. The website says Z class gets 100% miles. I made the rest of my travel decisions for the year based on that assurance. Even if a mistake was made on their end, they should honor it because, two weeks ago, I still had time to book a last minute trip to ensure I made it over the diamond line. But, by the 30th of December, that's a lot harder. I could really use some advocacy to ensure Delta does the right thing in this case.