I live in the United States, how can I purchase replacement wheels? I have the Junama Impulse, but the wheels went bad.
As a Polish pram, I am guessing you ordered the Junama Impulse online. If so, first, try to contact the original seller. They should have contact with the manufacturer or the official distributor. I mean, Junama parts (nor other spare parts) aren't often sold just so, it's usually on the retailer/customer service/producer to supply these on-demand.
If that doesn't help, try to contact the manufacturer directly (email@example.com). If they don't help, I am afraid you'll be in the market for a new stroller (system).
It is also good to consider that new wheels will come costly (it can be up to 100 USD + postage fee) and it will be the same, meaning they might get broken again. Sometimes thinking about a different brand/stroller model is savvier than replacing a faulty part. Just an idea.