mobile

I'm having very slow wifi and data on my ATT S6 Edge. Its only about 13 Mbps down and 10 Mbps up. My wifi does 50 Mbps down but should be about double that.
My previous phone, the LG G2 D800 was getting about 70 Mbps down on data in the same area. Just wondering of any of you are having the same problems. If its just me, it might be a hardware issue - have to return it :(
Thanks