Kicked out from buying

News: Welcome to the Canadian Paper Money Forum.

I received about 20 notes from the same company in the last year. Two of the notes the grading was EF/AU and the other was 62. when I received the notes the EF/AU was VF 30 and the 62 was AU 50.( I had them certified) I sent them back according to their terms. Yes I will get the money back. Now the company says they do not want me to use their website to buy notes ever again. Has any one else had this happen in the past?

Any reputable company would not do this.
If the company is a member of the Canadian Association of Numismatic Dealers, you can seek recourse through that body at CAND.org
If you paid with a credit card, you can also go through that channel.
Small claims court takes a long time but that is also available and just filing a claim can sometimes spur the seller into settling.
Also, try talking to other dealers who may be familiar with the company in question. Sometimes a bit of influence from other dealers can help.
Otherwise, it may be a harsh lesson for you, unfortunately and hopefully for the company in question, plenty of detrimental public relations fallout. However, be careful how you send out messages about this issue.

Let's not jump to conclusions.
Were the notes returned and, if so, did you receive a full refund for them?  And just for clarity, did they send you the incorrect notes, or were they the right notes that appeared to be lower grade according to your own assessments?