OT: Server-room climate monitoring

Hi all, apologies for the slightly OT post...

My server room is rather small and has recently had AC fitted to keep it
cool in the summer months - it is especially important now as we have just
installed a number of new servers which bumps up the temperature somewhat.

The AC is provided by our landlord and is non-redundant so I would like to
be notified via SMS/email if it fails. There are plenty of products on the
market that perform climate monitoring, but all require a valid internet
connection in order to send alerts - here's my problem - our leased line and
telephone provision is also non-redundant and provided by the landlord, so
in a power cut there would be no way of getting notified as both telephone
and internet instantly die, even though my UPS will happily power the
servers until the room heats up to sub-sahara temperatures. It's also
possible that both internet and leased line fail to power-up correctly after
a short outage, as happened last weekend.

Can anyone offer any help or suggest a solution? I'd love to see some kind
of cellular climate monitor that requires nothing than a SIM card...

Thanks
steve