Had a call from the facilities/housing officer,at a local American air base.Would i be interested in quoting on a 2/3 bed house,with a view to getting me on the books as a contractor,to cover all local bases,there are about 5 within about 15 miles of me !!
Oh yes please,had to supply prices for carpet cleaning,protector,flea treatment and tile and grout cleaning,don`t do tile and grout currently,but will be a nice add on for me 
I have done quite a few on the various bases round here,indirectly though,never had a problem,i know their march out`s are very very pernickety .
I did say that it is not always possible to get all stains out,they said they expect me to get everything out except Coolaide !!
They only pay by Visa,so it would be direct bank trans,they say their other people have card swipers,so my next question is who does a good deal on those ?
Also need a new fax machine,as typically mine died the other week
Good for you on being contacted.
Think it's already been hinted at that they are already calling all the shots, there has to be a meeting point in the middle here, especially regarding stain removal and payment.
If they are expecting "every"stain to come out then I would be very wary of getting payment from them if you can't do that, even if you have made it clear.
Up to you if you want to spend out on a card reader. May be good for the rest of your business, but don't get it just because of this "supposed" work.
Have worked for someone before and we did American airbases (not cleaning), no problem with straightforward invoicing, but everything had to be 150%( in their eyes) and if not the call backs, ate away at the profits.
I would make sure that "all" the cleans have to be arranged through the housing officer or can the tenants make their own arrangements. You have already done some "indirectly" as you say, so just check that out
