The bad service that we have received at swimrite centurion

Swimrite centurion services is something that I can recommend, our child was at a crechè when we enrolled her that was 2017, she now went to a primary school of which the school did not inform us that the school will still bill us , from our side we assumed that there services end at that school not that school and they is no need to cancel the contract what so ever, from 2018 our child has not been attending the swimrite sessions, today we are receiving a notice from JM debt collectors asking for R4487.00 and threatening to blacklist us, how do we pay for the services that we never used, and is not not the responsibility of the service provider to inform us when schools are changing since they were collecting the child from school? Why was swimrite not questioning after upon noticing if at all they keep records of the attendees as to why our child is not attending than just handing us over to someone without investigating? Their services are not satisfying, how can we be assisted? Where can we go?