I would suggest you were convicted long ago if there system is like Ontario.
You received Provincial Offences Tickets with an area and amount to pay out of court, you had 15 days to do this or plead "not guilty" and then a trial date would have been mailed to you.
If you failed to contact the court and plead guilty or not guilty then after 15 days a judge can find you guilty in your absense.
I don't know who you have been trying to contact but you need to contact the court, the address will be on the tickets.
The court will be able to tell you about these charges and if you have been convicted or not.
If you are convicted and fail to pay the fine, then your fine account will likely go into collection which can affect your credit ratings, even in the USA.
The judge can and most likely will place an arrest warrant on you, which means if you come to Canada, anywhere in Canada and get stopped by the police, you will be arrested.
Of course this is only on the people who received the tickets, no one else, and only if the Quebec laws are like Ontario.
This is how it works in Ontario.
It would be a good idea to contact the court and see where you stand as it is unlikely you will get anything from the court, the courts leave it up to you to find these things out.
Goodluck