To contact member services directly you can send an e-mail to : support@trustedhousesitters.com
I recommend that you do that for your voice to be heard as member services do not appear take any notice of the opinions expressed on the forum.
If you need to overlap sits frequently it may be worth getting an additional membership in your wife’s name ( using your refer a friend code ) for a discount ( currently 30% discount + you would get 3 months free membership added to your original account) . Then you would be able to use the second account to apply for sits where the dates overlap. Not ideal as your reviews won’t carry over to the second account but THS have stated categorically that they are not going reverse their decision on the overlap rule.
You could also ask member services for a special promo code on a second account. Homeowners who have two properties to list can get a discount on a second membership .
I assume that they offer the same offer for sitters, but haven’t seen this confirmed on the forum so you would need to check with member services.