For what it's worth I've made online purchases from both Diamond Edge and Groomers and found them both to be completely trustworthy and excellent to deal with.
My own preference is Groomers and I can honestly say that I haven't been disappointed in any way with their level of service. If you're not happy about dealing through their website then give them a phone. They're very knowledgable regarding the products they sell and can often advise you on the most suitable products for your needs.
My own experience of their aftersales service and support is awesome. I had a fault develop on some Andis clippers I had bought from them just a few months out of warranty and phoned them to arrange a repair. I was sent some loan clippers while mine were being repaired and, when mine were returned a week later a new motor had been fitted free of charge as they considered that it should not have failed in such a short time in domestic use. Several weeks later they contacted me to say that the manufacturers had found a bearing fault in the motor and I was sent a small gift as compensation.
Can't say better than that, reasonable prices, excellent product knowledge, fast delivery and brilliant customer support. I deal with them to this day.
Bob.