The "pay more, get less" mental math is a killer, even if the new rate is completely fair. Clients don't see market rates, they see their budget and their deliverables. you changed two variables at once, and their brain short-circuited.
If I'm rescuing this account, I separate the moves. Either keep the original deliverable and raise the price to reflect the actual value you're providing, or if capacity is the real issue, reframe the smaller package entirely. Stop selling video counts and start selling outcomes. Did that last campaign drive 300k+ qualified impressions or a specific lift in demo requests? that's the number they should be paying for. That reframe changes how every dollar lands.
and do not just roll over to $1000. You set a clear precedent that this was an intro rate. You're protecting your business model here. I'd hold at $1300 but offer a concession that costs me little but gives them perceived security: lock that rate in for a longer commitment, like six months, or include a tangible add-on that enhances the campaign, like an extra strategy session or priority turnaround. You give them a win to say yes without undermining the value of your work.