Lazy accounts department and harassment

Unfortunately I glad to use Lancet as its the only lab in my Dr's offices, an account was sent and it was paid and proof of payment sent to the stupid call centre. 2 weeks later I'm still been harassed for payment via sms and emails. You people are ****** lazy and even after I've sent you proof of payment you can use the reference and find the payment in your account. If this continues I will report you to the ombudsman, this is ridiculous and will definitely never use your services ever again.