madvapes is a very reputable vendor and doesn't sell stuff under false pretenses. If you feel those aren't R2v4 like they advertised you need to get ahold of them so they can make it right. If it isn't the right ones they would want to know. I'm sure they don't open each box and look so maybe it's something you need to tell them.
This was the first time I purchased from them and I've always heard great things about them. Being that these carto's were the first C-E2's I have ever had I just assumed they were the R4's because thats what I ordered. I'll contact them to see what they say, but in all honesty I've had these carto's for a month and have used about 4 of the 10 I purchased so far. I'm still shocked that these aren't R4's! I thought I had read someplace in that 6,000 page thread about the C-E2 cartos that the single plug design was one of the improvements made from the R3's to the R4's. Hmmmmm... Feeling a tad stupid right now. LOL