I'm paying for 6mbps and only getting 1.5?

I have AT&T wireless in a small apartment. I've only had it for 2 months. I use it for internet on my mac, iphone, and smart TV. It seems to run well on my TV, but my iphone and mac are running slowly when I try to download apps or stream video. I tested my speed, and it only came up as 1.5mbps. The only thing using the internet right now is my laptop.

What the heck? How do I fix this? Absolutely ridiculous.

If you go to the AT&T site and look at the ads, they'll probably say "… Up to 6 Mbps". This is how ISPs squirm out of being responsible for the internet speeds we get. There's usually no guarantee. Contact AT&T and get them to handle this problem. It should be their problem, not yours.

You are paying for UP TO 6 Mbps. That is how bandwidth is quoted for any account. What you actually get if it is a cable service depends how many others in the same area sharing the bandwidth. For DSL it depends on the state of cabling to your property and the distance from the exchange. If you are actually subscribing for wireless direct contact them, it could be problem with their transmissions reaching your apartment.

Because ISPs are ridiculous.

Google it before you ask here.