I phoned Ikea to find out what to do, and they said we should just take back the part that was broken. So Alexa drove it over there, only to find that they didn't have one of those in stock, and they'd have to specially order it in. The customer service droid took down my name and number, and was supposed to be calling me about it, but didn't. After a few days, I rang them and discovered that they'd lost the previous form, so another one was filled in. Still no one has rung me. I may have to contact them again.
[rest of post hastily made friends-only]