I just received a letter from this same company today. Same name, different PO Box, different phone number, different claims/disbursement agent, different amount in my cashier's check, different amount to pay as processing fee.
I immediately recognized it for what it is - mail fraud. I have reported it online here: https://www.recol.ca/
This is a Canadian agency which allows a person to report frauds online regardless of the type of fraud. I recommend that you report it to them, or to some other Canadian agency and also to your bank, your local police, and USPS, and the FBI.
Unfortunately, the cashier's check is probably not any good (as you have probably discovered by now) and you are out $1750. Had you waited for the check to clear your bank before sending the money you would be out nothing. The chances that you will get back the money you sent are about 0. The best you can hope for is that you have learned not to fall for this sort of thing, whether it is through the mail, phone, or email. Because you responded to this scam, you can expect to receive more scams. Many of these scammers share list of successful patsy's, so your name, address, and any other info you gave them is likely circulating as you read this.
I sure hope you didn't give them your DOB or Social Security number, because if you did you've really got a potential mess on your hands. If you did give out this info, then check your credit report ASAP.