Hello Tappi,
Better go & meet them to get to know the ACTUAL issue that's holding-up the payment.
It COULD be genuine delay from their end OR it COULD also be an attempt to skip your payment.......you wouldn't know unless you read their body language, which can happen only in a F2F.
And like James Win mentioned, LEARN to say NO too. It's always better to do some due deligence from your end before you sign-up any client. You will save yourself a lot of such trouble.
I had a Company in Bangalore who approached us but wanted to pay after 3 months [even with a Replacement Clause of 3 months]....though the skillsets & numbers were very comfortable for us.......we just said NO [even though we know many agencies are OK with such terms].
Also, pl note that what's written in the Agreement need not mean that the clauses will be adhered to to-the-dot. 1.5 months against 1 month isn't very high in the current market scenario.
However, advance Payments won't work in the Recruitment sector.....there are many agencies to chose from.
Getting associated with a larger Recruitment Company, that's stable & established, is one way to handle/preempt such situations....but here again you can't generalize every Pvt Ltd Company as a tome of fairness & promptness. You need to use your judgement well before deciding.
All the Best.
Rgds,
TS