Avoid using the Trainline App! FAQ on website regarding changes to tickets extremely misleading. Phone calls to customer service most unhelpful and, after being placed on hold on numerous occasions eventually transferred to the unrelated National rail network who hadn’t a clue why I’d been transferred to them. Email customer service polite but extremely unhelpful. Issue unresolved. Hours of time and endless emails simply repeating original generic email response. Felt that there was little understanding of issue raised or acknowledgment that point raised was properly investigated. Told there was no complaints procedure. Really!