GEN 4 Jimny undersealing wearing off

Hi, about 3 months ago I had the car expensively and professionally undersealed with Dinitrol. At the service today the mechanic said it was patchy and coming off, see a few pics. Surely underseal has to be fa? more enduring than that? Anyone had similar experience. The car has not been subject to powerwashing.
Thanks

Yep, taking it back to him: in fairness he said he's sort it out but I need to know what happened as this looks worse than having none at all!

It was about 9 months old, nothing added over the original somewhat random pattern of Suzuki underbody treatment. We live up a forest track so it has remained coated in mud over the underseal for long periods, maybe something in that mud has a penetrating effect although I can't think why?

Blimey, done mine myself and its still good couple of 20p area's but I would certainly be turning up at that place for them to explain that.

It's about 10 months since mine was done and still looks like it did the day after it was done (apart from where I have rubbed it off going off road).
Where did you get it done?
How long did they have your car?
Do they provide a free annual check and touch up? Mine does
And if you don't mind me asking, how much did you pay?

I'm watching this with interest as I'm just about to get mine booked in for the treatment.

I don't want to mention the supplier by name till they've had a chance to rectify, which they have said they will do and that this is 'highly unusual' . The place gets a very good reputation and they had it several days. If I recall correctly it was over £600.
They do give a free annual check as well

All that sounds good then. I paid £650 +VAT.
Had mine 3 days.
1st to power wash and steam clean, then dry over night
2nd to apply first thin clear coat wax
3rd to apply outer harder wearing black wax
As per recommended on the Dinatrol website.

pretty much as I remember they did to my car including the hard wearing layer (that cost a bit extra I think). More I think of it I'm suspecting long term smothering in the mud off the forest road has a deleterious effect. The area is famous for its 'acid rain' so maybe this is like having an acidic coat??
Having said that how energetically can one hose the mud off without blasting off the underseal, obviously if a pressure washer is used I presume it would strip the dinotrol stuff off? Leaves a conundrum as to how to remove the mud while not stripping the underseal?

When I asked about jet washing they told me it would be fine. Having said that I do treat the underneath the same as I would treat the paintwork when jet washing. i.e. On my Karcher having the Vari-nozzle on the car setting and not getting too close.