Wrong section.
I have doubt. This does not look like a currency exchange thread but seems to be a service. OP is looking for someone who will send his USDT and that guy will cash out to buy the dog for him. So it's perfectly a service rather than currency exchange.
OP as shasan suggested, you may consider posting it on Russian section to get targeted users who will be interested in it. Also if you offer them some incentive then they will happily do it. No one will want to take a job or find interest without having any incentive.