Sounds like Basic Economy to me. Those are the only non-canceable, non-changeable fares UA sells ex-US. If you booked directly on the UA site, it would have given you multiple warnings, including one that requires you click a checkbox that you understand the rules, with the option right next to it to buy regular economy. It is literally impossible to miss that (though I suppose those really wanting the lower fares could ignore the big Xs in what you don't get, but would be impossible not to know you didn't check the box).
One giveaway on whether this is actually BE or not is whether it allows you to select a seat (without a fee). If the answer is yes, it is not a BE ticket. If it is requiring a fee, then it is BE (or the system is interpreting it as one). Another is the fare class. Domestic BE books into N - so if it is N, it is BE, and if it is anything else, it is not. Your eticket itinerary and receipt email will show the booking class will say what that is. You can also click the 'fare rules' link just under the itinerary in your account - it will show you the rules - you can open the penalties to find out what those should be. It will also show you the fare basis - there is a code in their near the end that specifies its a BE fare - I forget what it is but there are others on here who can probably point out what to look for there.
One thing strange is the ability to upgrade to PP. I know things about BE has changed (and I don't personally buy those fares), but I thought there were no ability to upgrade classes, even to E+, much less PP. Unless this has changed (and someone in here I'm sure can verify), it could point to a bug - given it's Saturday, this happens often as UA updates its systems - wait until tomorrow and see if something changes. Other option, of course, is to call UA and find out.
If this is actually in BE, as mentioned above, you can pay a fee to convert the ticket to regular economy - you still can't refund it, but you can make changes or cancel and get the fare back in an FFC (original ticket cost - the fee to 'upgrade' to regular economy is a fee and will not be returned to you in the FFC).