Reserve Price is unfortunately a very well known, very long running problem that will only be resolved when the platform migrates to the Beta Site that is currently up and running, but not all singing, all dancing. I had refunds before, but only by taking a screenshot of the RP, but been a while since I've bothered, and not sure they are even doing that anymore.
They will just reply to the email you sent, don't worry about the ticket. They are just really slow to respond at the moment, presumably because of the influx of new users this month.
If you can be patient, just wait for the email (I'm still waiting on an answer from over a month ago), but if you haven't got a screenshot then don't think you'll get any joy.
Otherwise, you can get on with it now knowing Reserve Price doesn't work. Take it as a sign you should have never of tried to sell the boy Rashford :)