Mortar turned to sand

[NPR]

At the end of October I had my patio laid in Indian stone. Now I've come to clean it after the winter I find most of the pointing between the stones has turned to loose sand. It's that soft a screwdriver can be easily pushed right through it.
I've phone the company who laid it, they blame the bad winter and accept no responsibility.
Can I ask the experts here:-
1) Is it normal or acceptable for the pointing to crumble to sand over one winter.
2) If I can't get the company to correct this I'm thinking of doing the work myself but need a few pointer.
If I power wash the old pointing out is this amount of water going between the stones likely to disturb the bedding of them?
Google'g re-pointing, a dry mix seems the favoured method but the recommended mix is anything from 1:1 to 8:1 and type of sand varies from plastering sand to sharp sand.
Advice on the mix and type of sand / cement would be appreciated, something which will not stain the Indian sandstone.

[msh paving]

all about pointing

read this or thisread me

MSH

[lutonlagerlout]

no mortar should turn to sand
was it frosty when they did it?
if the mix was too weak that is their problem not yours
the mild winters we have had till now do not mean ppl can blame 1 bad winter for poor workmanship
LLL

[Triggaaar]

The Romex product promises a lot, but how does a DIYer protect large patio areas from rain for 24 hours? It's not economical to buy their rain protection gear for a one off project.

[msh paving]

The gtfk product does not need protection from rain,as you use water to clean up with,i use it alot MSH