Inventory Planner by Sage - anyone else get burned?

Curious if anyone else has been through this or if we just got unlucky.

We're a small retailer, needed solid inventory sync. Talked to Inventory Planner, explained exactly what we needed, got told yeah no problem we can do that despite many concerns from our side, mostly based on them essentially not asking any of the question one would expect about our ERP, which they had no experience with.

Fast forward a few months: integration was supposed to be simple but we ended up hiring outside consultants just to make sense of it. Every time there was a middleware update we basically had to start over. Duplicates everywhere, stock levels wrong, the whole thing never actually worked, like not even close.

Senior managers tell us there's "no breach of contract" but hey, we can pay for more professional services if we want. After months of back and forth radio silence from them.

So... is this normal for them? Did anyone actually get this working? Or did we just waste a year of our lives?

Can anybody recommend something similar, is netstock better?

Essentially we want to allocate stock from our central warehouse based on sales in a semi-automated way. If more details are helpful, I'll gladly provide them.