Problems with xfi and pod extenders

New client here....installed a 400 download speed plan on 6/15.  However, with tech still here, walked around house and checked speeds.  They were ridiculously slow, less than 80 mbps, in most places except right in front of the modem, Gateway, Xfinity provided.  This is their new top of the line modem/router.  Because of configuration of house, when ordering I asked about extenders and rep said, if needed, the X pods would be provided free.  Very nice.  On 6/15, install tech said he didn't have the pods and to go to the local store.  Yes, they will be free.  At store, rep told a different story.  Pods are free, after a home evaluation.  Couldn't explain how or when the evaluation would be done or why needed to wait, but said try a new modem.  And if I wanted to buy the pods they were $120.  Off I went with the new modem.  Sadly, that one wouldn't connect.  Rep on phone did provisional signals tests and repowered it but it wouldn't connect.  His suggestions, go back to the original one.  That I did and had service, not great wifi.  Called again on 6/16 and the rep said home evaluation happens automatically, takes two weeks and no guarantee that pods will be provided.  She suggested a new tech be sent at a cost of $100 but that she would credit that cost back.  New tech came, and installed yet another modem/router.  Wifi improved moderately but still in the 100 mbps range which is well below the plan I am paying for. And in parts of the house either there was no service or less than 10 mbps range. Called his supervisor and he suggested I connect the Xfinity modem to the extender I already owned.  That would solve the problem.  However, I am paying a monthly fee for XFi and if I use my own extender the XFi would be negated.  Nothing about this makes sense.  

I went back to the store, I had to return the second modem.  I asked about the extenders and about the 30 day money back guarantee.  Rep said yes they will do a home evaluation.  It takes 2 weeks and gave me a id number for the evaluation.  30 day guarantee starts on day the installation was complete, which per the records he had was 6/16.  Interestingly, the phone rep said the 30 day guarantee started on the day the equipment was delivered to my house, 6/09 regardless of the fact that the modem wouldn't connect.  

I am pretty close to returning it all.  I didn't cancel my other internet service so can do so without interruption or additional costs.  I am just so confused as to why the process is so cumbersome and why the reps keep telling me different versions of what is and isn't available or provided.  

Suggestions?