iPhone 5C host-spot problem.

I've got problem with my iPhone 5c.

I don't have in my first page of settings switch to turn on/off hotspot (my friend with 5s (os 7.1.1 as mine) does have one), so I need to get to options / cellular / personal hot spot - which in few seconds turned into the blue inscription "set up personal hotspot". When I'll tap on it, it always says "To enable personal hotspot on this account, contact PLAY (play is my phone-services provider).

Please help!

I bought this phone from my friend from work. We've got the same phone-services provider which I called - they said that in my VPN, MMS etc. options is everything allright, so the problem is not on their side. Network, massages are working corectly.