
Hi
So sorry you're having such troubles.
I applied on line for M&S insurance on 11th May 2005. I wanted cover to start from 20th May as that was they day we were due to pick up our puppy. I didn't hear anything from them either so gave them a call to confirm that the policy had been accepted. They confirmed that it had and documentation had been sent. I still hadn't heard anyting by 1st June so I rang again and they agreed to re-send the paperwork. I have now received 2 lots of paperwork! My policy shows that cover started on the day that I first applied, not 20th as requested.
Not sure that you needed all this detail but I think I'm basically reiterating what has been previously said (much more concisely than I am doing). Give M&S a call as soon as possible (0800 072 0119) and check the start date of the policy. As long as the date of first diagnosis of the problem is after the start date, you should be covered.
Hope it all turns for the best and your boy is ok.