Don"t assume that they don't love and appreciate them. They probably do and have just been caught up in their busy lives. I bet the next time they see you they'll thank you. However I do agree that calling them to make sure they really arrived would not be out of line.
I sent a beautiful baby quilt to a nice and nephew last year and didn't hear from them for months. I worried that they hadn't received it also but then my SIL (she didn't know I'd sent them a quilt) said she had seen them at a family gathering and asked where they got the beautiful baby quilt and they told her I'd made it. My SIL said it was just gorgeous. I was very relieved that they had gotten it and were using it. Then a couple months later I got a lengthy Thank you letter from them with an apology for the lateness and saying how much they loved the quilt and how the baby slept with it every night.
So keep the faith...I don't know how they couldn't love those beautiful quilts you sent them.