"if that's the case you can't combine and send with only one service."

I'm sorry but I think you've misunderstood again, I'll do as I wish thank you and my customers are extremely grateful at the significant savings they make on postage by orders being combined regardless of what service they pick. One customer save £22 the other day, another £8 this morning and one the other day nearly £20 again, you think they'd be happy paying more to have stuff come in different parcels?

Yet me as your customer is seriously frustrated at wasting an hour of my life changing half my listings so they all read "2nd Class large letter" instead of half reading "2nd Class" to stop you stealing yet another small piece of my income without good cause.

I don't know why I did that to begin with (I also don't know why you have 4 options for 2nd class, what is the point?), racking up listings and using sell similar has caused this yet your site is badly designed to both correct the matter and in the manner in which it takes extra fees.