I had systenmech as a trial period but then it was cancelled so why have I still been charged £3-99 for it . Icancelled it in plenty time so you have no right to go and take money that's not yours so could you put it back asap

Umm, so why are you telling us? This is an all too common occurrence. You subscribe for something, and either forget to cancel or the cancellation gets lost. You contact the vendor and demand that billing stops and a refund be issued. Or, if this is being automatically debited from a credit card or bank account, you tell them to stop making deductions. If it's a credit card you tell them the deductions were erroneous and have them refunded.